Mason City Muni AP Weather Records (USW00014940)
Record envelope, standing records and threshold days for Mason City Muni AP (USW00014940), Iowa, United States, with 79 years of record.
Key Facts for Mason City Muni AP
- Mason City Muni AP (USW00014940) is a weather station in Iowa, United States at 43.15 latitude and -93.33 longitude, 362 m (1,188 ft) above sea level.
- The station reports from 1948 to 2026, 79 years of record.
- 1,464 records set at Mason City Muni AP still stand.
- Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
- Mason City Muni AP set a daily record high maximum temperature of 31.7 C (89.1 F) on 11 October 2026 (provisional).
Provisional Records
Records set in the last 60 days are provisional until they clear the revision window.
About the Station
- Location: Iowa, United States, 43.15 latitude, -93.33 longitude.
- Elevation: 362 m (1,188 ft).
- Period of record: 1948 to 2026, 79 years.
- Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
6 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 16.7 C (62.1 F) | -35.0 C (-31.0 F) | 8.3 C (46.9 F) | -28.9 C (-20.0 F) |
| Feb | 22.8 C (73.0 F) | -35.6 C (-32.1 F) | 16.7 C (62.1 F) | -17.2 C (1.0 F) |
| Mar | 28.9 C (84.0 F) | -33.3 C (-27.9 F) | 28.3 C (82.9 F) | -17.8 C (0.0 F) |
| Apr | 33.9 C (93.0 F) | -14.4 C (6.1 F) | 28.3 C (82.9 F) | -7.2 C (19.0 F) |
| May | 37.2 C (99.0 F) | -5.6 C (21.9 F) | 32.2 C (90.0 F) | -1.7 C (28.9 F) |
| Jun | 39.4 C (102.9 F) | 2.2 C (36.0 F) | 32.2 C (90.0 F) | 8.3 C (46.9 F) |
| Jul | 40.0 C (104.0 F) | 5.6 C (42.1 F) | 32.8 C (91.0 F) | 11.7 C (53.1 F) |
| Aug | 38.3 C (100.9 F) | 1.7 C (35.1 F) | 30.6 C (87.1 F) | 9.4 C (48.9 F) |
| Sep | 37.2 C (99.0 F) | -4.4 C (24.1 F) | 32.2 C (90.0 F) | 5.6 C (42.1 F) |
| Oct | 35.0 C (95.0 F) | -11.1 C (12.0 F) | 31.7 C (89.1 F) | 3.3 C (37.9 F) |
| Nov | 26.1 C (79.0 F) | -26.7 C (-16.1 F) | n/a | n/a |
| Dec | 20.6 C (69.1 F) | -32.2 C (-26.0 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1948 | 19 |
| 1949 | 12 |
| 1950 | 35 |
| 1951 | 28 |
| 1952 | 11 |
| 1953 | 15 |
| 1954 | 8 |
| 1955 | 22 |
| 1956 | 14 |
| 1957 | 5 |
| 1958 | 14 |
| 1959 | 20 |
| 1960 | 19 |
| 1961 | 11 |
| 1962 | 27 |
| 1963 | 32 |
| 1964 | 25 |
| 1965 | 36 |
| 1966 | 22 |
| 1967 | 28 |
| 1968 | 22 |
| 1969 | 19 |
| 1970 | 22 |
| 1971 | 13 |
| 1972 | 31 |
| 1973 | 14 |
| 1974 | 26 |
| 1975 | 16 |
| 1976 | 24 |
| 1977 | 26 |
| 1978 | 12 |
| 1979 | 14 |
| 1980 | 13 |
| 1981 | 22 |
| 1982 | 11 |
| 1983 | 38 |
| 1984 | 16 |
| 1985 | 30 |
| 1986 | 18 |
| 1987 | 21 |
| 1988 | 30 |
| 1989 | 19 |
| 1990 | 14 |
| 1991 | 31 |
| 1992 | 13 |
| 1993 | 15 |
| 1994 | 17 |
| 1995 | 14 |
| 1996 | 16 |
| 1997 | 16 |
| 1998 | 18 |
| 1999 | 12 |
| 2000 | 28 |
| 2001 | 18 |
| 2002 | 13 |
| 2003 | 15 |
| 2004 | 17 |
| 2005 | 17 |
| 2006 | 15 |
| 2007 | 11 |
| 2008 | 7 |
| 2009 | 14 |
| 2010 | 9 |
| 2011 | 12 |
| 2012 | 41 |
| 2013 | 15 |
| 2014 | 20 |
| 2015 | 6 |
| 2016 | 5 |
| 2017 | 18 |
| 2018 | 23 |
| 2019 | 12 |
| 2020 | 25 |
| 2021 | 21 |
| 2022 | 10 |
| 2023 | 24 |
| 2024 | 23 |
| 2025 | 11 |
| 2026 | 8 |
All-Time Record Progression
13 new records| Date | Kind | Detail |
|---|---|---|
| 1979-01-24 | Record snow depth | Record snow depth 71.1 cm (28.0 in) |
| 1979-01-27 | Record snow depth | Record snow depth 73.7 cm (29.0 in) |
| 1979-01-28 | Record snow depth | Record snow depth 76.2 cm (30.0 in) |
| 1979-02-02 | Record snow depth | Record snow depth 78.7 cm (31.0 in) |
| 1979-02-12 | Record snow depth | Record snow depth 83.8 cm (33.0 in) |
| 1980-07-07 | Record high maximum temperature | Record high maximum temperature 40.0 C (104.0 F) |
| 1982-01-22 | Record daily snowfall | Record daily snowfall 30.5 cm (12.0 in) |
| 1983-12-18 | Record low maximum temperature | Record low maximum temperature -25.0 C (-13.0 F) |
| 1983-12-19 | Record low maximum temperature | Record low maximum temperature -25.6 C (-14.1 F) |
| 1983-12-22 | Record low maximum temperature | Record low maximum temperature -26.1 C (-15.0 F) |
| 1983-12-23 | Record low maximum temperature | Record low maximum temperature -28.9 C (-20.0 F) |
| 1996-02-02 | Record low minimum temperature | Record low minimum temperature -35.6 C (-32.1 F) |
| 2018-03-24 | Record daily snowfall | Record daily snowfall 31.5 cm (12.4 in) |
Wettest Day of Each Month
Aug: 160.8 mm (6.3 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 28.4 mm (1.1 in) | 22 January 1982 |
| Feb | 41.1 mm (1.6 in) | 27 February 1948 |
| Mar | 52.8 mm (2.1 in) | 30 March 2006 |
| Apr | 69.6 mm (2.7 in) | 19 April 2005 |
| May | 116.6 mm (4.6 in) | 21 May 2004 |
| Jun | 136.1 mm (5.4 in) | 18 June 1954 |
| Jul | 104.9 mm (4.1 in) | 24 July 2015 |
| Aug | 160.8 mm (6.3 in) | 22 August 1954 |
| Sep | 132.1 mm (5.2 in) | 12 September 1978 |
| Oct | 69.9 mm (2.8 in) | 11 October 1986 |
| Nov | 59.7 mm (2.4 in) | 9 November 1975 |
| Dec | 40.6 mm (1.6 in) | 27 December 1982 |
Period of Record Coverage
1948 to 2026| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1948 | 366 | 100% | Yes |
| 1949 | 365 | 100% | Yes |
| 1950 | 365 | 100% | Yes |
| 1951 | 363 | 99% | Yes |
| 1952 | 366 | 100% | Yes |
| 1953 | 365 | 100% | Yes |
| 1954 | 365 | 100% | Yes |
| 1955 | 365 | 100% | Yes |
| 1956 | 365 | 100% | Yes |
| 1957 | 364 | 100% | Yes |
| 1958 | 365 | 100% | Yes |
| 1959 | 365 | 100% | Yes |
| 1960 | 366 | 100% | Yes |
| 1961 | 365 | 100% | Yes |
| 1962 | 365 | 100% | Yes |
| 1963 | 365 | 100% | Yes |
| 1964 | 365 | 100% | Yes |
| 1965 | 365 | 100% | Yes |
| 1966 | 365 | 100% | Yes |
| 1967 | 365 | 100% | Yes |
| 1968 | 366 | 100% | Yes |
| 1969 | 365 | 100% | Yes |
| 1970 | 365 | 100% | Yes |
| 1971 | 364 | 100% | Yes |
| 1972 | 366 | 100% | Yes |
| 1973 | 365 | 100% | Yes |
| 1974 | 365 | 100% | Yes |
| 1975 | 365 | 100% | Yes |
| 1976 | 366 | 100% | Yes |
| 1977 | 365 | 100% | Yes |
| 1978 | 365 | 100% | Yes |
| 1979 | 365 | 100% | Yes |
| 1980 | 366 | 100% | Yes |
| 1981 | 365 | 100% | Yes |
| 1982 | 364 | 100% | Yes |
| 1983 | 365 | 100% | Yes |
| 1984 | 366 | 100% | Yes |
| 1985 | 364 | 100% | Yes |
| 1986 | 365 | 100% | Yes |
| 1987 | 365 | 100% | Yes |
| 1988 | 366 | 100% | Yes |
| 1989 | 365 | 100% | Yes |
| 1990 | 365 | 100% | Yes |
| 1991 | 365 | 100% | Yes |
| 1992 | 366 | 100% | Yes |
| 1993 | 365 | 100% | Yes |
| 1994 | 365 | 100% | Yes |
| 1995 | 365 | 100% | Yes |
| 1996 | 365 | 100% | Yes |
| 1997 | 365 | 100% | Yes |
| 1998 | 365 | 100% | Yes |
| 1999 | 365 | 100% | Yes |
| 2000 | 366 | 100% | Yes |
| 2001 | 365 | 100% | Yes |
| 2002 | 365 | 100% | Yes |
| 2003 | 364 | 100% | Yes |
| 2004 | 366 | 100% | Yes |
| 2005 | 364 | 100% | Yes |
| 2006 | 365 | 100% | Yes |
| 2007 | 365 | 100% | Yes |
| 2008 | 366 | 100% | Yes |
| 2009 | 365 | 100% | Yes |
| 2010 | 365 | 100% | Yes |
| 2011 | 365 | 100% | Yes |
| 2012 | 366 | 100% | Yes |
| 2013 | 365 | 100% | Yes |
| 2014 | 365 | 100% | Yes |
| 2015 | 365 | 100% | Yes |
| 2016 | 366 | 100% | Yes |
| 2017 | 365 | 100% | Yes |
| 2018 | 365 | 100% | Yes |
| 2019 | 365 | 100% | Yes |
| 2020 | 366 | 100% | Yes |
| 2021 | 365 | 100% | Yes |
| 2022 | 364 | 100% | Yes |
| 2023 | 365 | 100% | Yes |
| 2024 | 366 | 100% | Yes |
| 2025 | 365 | 100% | Yes |
| 2026 | 285 | 78% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 11 October 2026 | Mason City Muni AP, US | daily high max (Provisional) | 31.7 C (89.1 F) | 2.8 C (5.0 F) | 65 years | 30 of 100 (Routine) |
| 10 October 2026 | Mason City Muni AP, US | daily high max (Provisional) | 30.0 C (86.0 F) | 1.1 C (2.0 F) | 64 years | 27 of 100 (Routine) |
| 4 September 2026 | Mason City Muni AP, US | daily high min (Tie, Provisional) | 21.7 C (71.1 F) | tie | 65 years | 6 of 100 (Routine) |
| 3 September 2026 | Mason City Muni AP, US | daily high min (Provisional) | 21.1 C (70.0 F) | 0.5 C (0.9 F) | 43 years | 20 of 100 (Routine) |
| 11 August 2026 | Mason City Muni AP, US | daily high min (Tie) | 21.7 C (71.1 F) | tie | 37 years | 4 of 100 (Routine) |
| 29 June 2026 | Mason City Muni AP, US | daily high min | 24.4 C (75.9 F) | 0.5 C (0.9 F) | 35 years | 18 of 100 (Routine) |
| 28 June 2026 | Mason City Muni AP, US | daily rain | 35.6 mm (1.4 in) | 5.4 mm (0.21 in) | 28 years | 18 of 100 (Routine) |
| 13 April 2026 | Mason City Muni AP, US | daily high min | 11.7 C (53.1 F) | 1.7 C (3.1 F) | 48 years | 24 of 100 (Routine) |
| 30 March 2026 | Mason City Muni AP, US | daily high max | 28.3 C (82.9 F) | 2.7 C (4.9 F) | 59 years | 27 of 100 (Routine) |
| 21 March 2026 | Mason City Muni AP, US | daily high max | 27.8 C (82.0 F) | 5.0 C (9.0 F) | 4 years | 14 of 100 (Routine) |
| 16 March 2026 | Mason City Muni AP, US | daily low max | -11.1 C (12.0 F) | 7.8 C (14.0 F) | 65 years | 36 of 100 (Notable) |
| 6 March 2026 | Mason City Muni AP, US | daily rain | 29.7 mm (1.2 in) | 11.4 mm (0.4 in) | 31 years | 31 of 100 (Routine) |
| 27 February 2026 | Mason City Muni AP, US | daily high max | 16.7 C (62.1 F) | 2.3 C (4.1 F) | 10 years | 13 of 100 (Routine) |
| 15 February 2026 | Mason City Muni AP, US | daily high max | 14.4 C (57.9 F) | 2.7 C (4.9 F) | 44 years | 23 of 100 (Routine) |
| 23 January 2026 | Mason City Muni AP, US | daily low max | -23.3 C (-9.9 F) | 1.6 C (2.9 F) | 63 years | 27 of 100 (Routine) |
| 13 January 2026 | Mason City Muni AP, US | daily high min (Tie) | 0.0 C (32.0 F) | tie | 68 years | 6 of 100 (Routine) |
| 8 January 2026 | Mason City Muni AP, US | daily rain | 18.0 mm (0.7 in) | 11.9 mm (0.5 in) | 62 years | 20 of 100 (Routine) |
| 25 December 2025 | Mason City Muni AP, US | daily high min (Tie) | 0.6 C (33.1 F) | tie | 2 years | 1 of 100 (Routine) |
| 4 December 2025 | Mason City Muni AP, US | daily low min | -25.0 C (-13.0 F) | 2.2 C (4.0 F) | 34 years | 19 of 100 (Routine) |
| 29 November 2025 | Mason City Muni AP, US | daily snowfall | 18.0 cm (7.1 in) | 3.8 cm (1.5 in) | 36 years | 27 of 100 (Routine) |
Climate Trend
78 complete years, 1948 to 2025| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1948 | 7.5 C | +0.05 C |
| 1949 | 7.7 C | +0.22 C |
| 1950 | 5.3 C | -2.22 C |
| 1951 | 5.3 C | -2.22 C |
| 1952 | 7.4 C | -0.07 C |
| 1953 | 8.0 C | +0.55 C |
| 1954 | 8.0 C | +0.54 C |
| 1955 | 7.5 C | +0.00 C |
| 1956 | 7.1 C | -0.40 C |
| 1957 | 7.3 C | -0.17 C |
| 1958 | 7.3 C | -0.21 C |
| 1959 | 7.0 C | -0.47 C |
| 1960 | 7.1 C | -0.42 C |
| 1961 | 6.7 C | -0.75 C |
| 1962 | 7.0 C | -0.51 C |
| 1963 | 7.5 C | +0.03 C |
| 1964 | 8.0 C | +0.49 C |
| 1965 | 7.2 C | -0.28 C |
| 1966 | 7.1 C | -0.41 C |
| 1967 | 6.6 C | -0.86 C |
| 1968 | 7.3 C | -0.17 C |
| 1969 | 6.0 C | -1.44 C |
| 1970 | 6.8 C | -0.69 C |
| 1971 | 6.8 C | -0.66 C |
| 1972 | 5.9 C | -1.55 C |
| 1973 | 8.4 C | +0.88 C |
| 1974 | 7.4 C | -0.05 C |
| 1975 | 7.8 C | +0.28 C |
| 1976 | 7.6 C | +0.16 C |
| 1977 | 7.7 C | +0.20 C |
| 1978 | 6.3 C | -1.17 C |
| 1979 | 5.7 C | -1.75 C |
| 1980 | 7.6 C | +0.16 C |
| 1981 | 8.3 C | +0.81 C |
| 1982 | 6.6 C | -0.90 C |
| 1983 | 7.5 C | -0.01 C |
| 1984 | 7.3 C | -0.17 C |
| 1985 | 6.6 C | -0.85 C |
| 1986 | 7.7 C | +0.22 C |
| 1987 | 9.5 C | +2.05 C |
| 1988 | 7.7 C | +0.23 C |
| 1989 | 6.8 C | -0.70 C |
| 1990 | 8.5 C | +0.98 C |
| 1991 | 7.8 C | +0.33 C |
| 1992 | 7.5 C | +0.05 C |
| 1993 | 6.3 C | -1.19 C |
| 1994 | 7.3 C | -0.21 C |
| 1995 | 7.4 C | -0.04 C |
| 1996 | 6.1 C | -1.39 C |
| 1997 | 7.2 C | -0.28 C |
| 1998 | 9.4 C | +1.94 C |
| 1999 | 8.5 C | +1.06 C |
| 2000 | 7.9 C | +0.39 C |
| 2001 | 7.8 C | +0.35 C |
| 2002 | 8.3 C | +0.79 C |
| 2003 | 7.3 C | -0.21 C |
| 2004 | 7.5 C | +0.03 C |
| 2005 | 8.5 C | +1.02 C |
| 2006 | 8.7 C | +1.25 C |
| 2007 | 7.8 C | +0.33 C |
| 2008 | 6.3 C | -1.21 C |
| 2009 | 6.7 C | -0.82 C |
| 2010 | 7.6 C | +0.07 C |
| 2011 | 7.9 C | +0.39 C |
| 2012 | 9.9 C | +2.41 C |
| 2013 | 6.8 C | -0.73 C |
| 2014 | 6.0 C | -1.48 C |
| 2015 | 8.5 C | +0.97 C |
| 2016 | 9.0 C | +1.51 C |
| 2017 | 8.4 C | +0.92 C |
| 2018 | 7.2 C | -0.29 C |
| 2019 | 6.8 C | -0.72 C |
| 2020 | 8.1 C | +0.64 C |
| 2021 | 8.7 C | +1.22 C |
| 2022 | 6.8 C | -0.64 C |
| 2023 | 8.8 C | +1.32 C |
| 2024 | 9.6 C | +2.11 C |
| 2025 | 8.5 C | +1.06 C |
The annual mean temperature here has risen by 0.2 C (0.1 to 0.2) per decade over 1948 to 2025. In Fahrenheit: 0.3 F (0.1 to 0.4) per decade. The slope is a straight line fitted to 78 complete years; the brackets give its 95 percent interval.
| Measure | Per decade (C) | Per decade (F) | Period | Complete years | Reading |
|---|---|---|---|---|---|
| Annual mean temperature | 0.2 C (0.1 to 0.2) per decade | 0.3 F (0.1 to 0.4) per decade | 1948 to 2025 | 78 | Rise |
| Mean daily maximum | 0.2 C (0.1 to 0.3) per decade | 0.3 F (0.1 to 0.5) per decade | 1948 to 2025 | 78 | Rise |
| Mean daily minimum | 0.13 C (0.05 to 0.22) per decade | 0.2 F (0.1 to 0.4) per decade | 1948 to 2025 | 78 | Rise |
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1948 to 2026| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 40.0 C (104.0 F) | 1980 | 35.6 C (96.1 F) | 79 |
| Coldest night (TNn) | -35.6 C (-32.1 F) | 1996 | -28.9 C (-20.0 F) | 79 |
| Wettest day (Rx1day) | 160.8 mm (6.3 in) | 1954 | 62.0 mm (2.4 in) | 79 |
| Wettest five days (Rx5day) | 271.0 mm (10.7 in) | 1954 | 93.3 mm (3.7 in) | 79 |
| Longest dry spell (CDD) | 58 days | 1952 | 24 days | 79 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1948 | 37.8 C (100.0 F) |
| 1949 | 35.0 C (95.0 F) |
| 1950 | 32.8 C (91.0 F) |
| 1951 | 32.2 C (90.0 F) |
| 1952 | 33.3 C (91.9 F) |
| 1953 | 36.1 C (97.0 F) |
| 1954 | 35.0 C (95.0 F) |
| 1955 | 36.7 C (98.1 F) |
| 1956 | 36.1 C (97.0 F) |
| 1957 | 35.0 C (95.0 F) |
| 1958 | 33.9 C (93.0 F) |
| 1959 | 35.0 C (95.0 F) |
| 1960 | 36.1 C (97.0 F) |
| 1961 | 36.1 C (97.0 F) |
| 1962 | 32.8 C (91.0 F) |
| 1963 | 36.7 C (98.1 F) |
| 1964 | 35.0 C (95.0 F) |
| 1965 | 38.3 C (100.9 F) |
| 1966 | 35.6 C (96.1 F) |
| 1967 | 34.4 C (93.9 F) |
| 1968 | 35.6 C (96.1 F) |
| 1969 | 33.3 C (91.9 F) |
| 1970 | 38.9 C (102.0 F) |
| 1971 | 35.6 C (96.1 F) |
| 1972 | 35.6 C (96.1 F) |
| 1973 | 36.1 C (97.0 F) |
| 1974 | 37.8 C (100.0 F) |
| 1975 | 35.0 C (95.0 F) |
| 1976 | 38.9 C (102.0 F) |
| 1977 | 36.1 C (97.0 F) |
| 1978 | 36.1 C (97.0 F) |
| 1979 | 33.9 C (93.0 F) |
| 1980 | 40.0 C (104.0 F) |
| 1981 | 34.4 C (93.9 F) |
| 1982 | 36.1 C (97.0 F) |
| 1983 | 37.8 C (100.0 F) |
| 1984 | 36.7 C (98.1 F) |
| 1985 | 39.4 C (102.9 F) |
| 1986 | 34.4 C (93.9 F) |
| 1987 | 37.8 C (100.0 F) |
| 1988 | 39.4 C (102.9 F) |
| 1989 | 36.7 C (98.1 F) |
| 1990 | 38.3 C (100.9 F) |
| 1991 | 35.6 C (96.1 F) |
| 1992 | 33.3 C (91.9 F) |
| 1993 | 32.2 C (90.0 F) |
| 1994 | 33.9 C (93.0 F) |
| 1995 | 37.8 C (100.0 F) |
| 1996 | 34.4 C (93.9 F) |
| 1997 | 35.0 C (95.0 F) |
| 1998 | 35.0 C (95.0 F) |
| 1999 | 35.6 C (96.1 F) |
| 2000 | 35.0 C (95.0 F) |
| 2001 | 35.0 C (95.0 F) |
| 2002 | 35.6 C (96.1 F) |
| 2003 | 34.4 C (93.9 F) |
| 2004 | 32.8 C (91.0 F) |
| 2005 | 34.4 C (93.9 F) |
| 2006 | 36.7 C (98.1 F) |
| 2007 | 36.1 C (97.0 F) |
| 2008 | 32.8 C (91.0 F) |
| 2009 | 33.9 C (93.0 F) |
| 2010 | 35.0 C (95.0 F) |
| 2011 | 37.2 C (99.0 F) |
| 2012 | 37.2 C (99.0 F) |
| 2013 | 37.2 C (99.0 F) |
| 2014 | 32.8 C (91.0 F) |
| 2015 | 35.0 C (95.0 F) |
| 2016 | 35.6 C (96.1 F) |
| 2017 | 35.0 C (95.0 F) |
| 2018 | 36.7 C (98.1 F) |
| 2019 | 34.4 C (93.9 F) |
| 2020 | 35.6 C (96.1 F) |
| 2021 | 38.9 C (102.0 F) |
| 2022 | 35.0 C (95.0 F) |
| 2023 | 38.3 C (100.9 F) |
| 2024 | 35.0 C (95.0 F) |
| 2025 | 33.9 C (93.0 F) |
| 2026 | 32.8 C (91.0 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1948 | -31.7 C (-25.1 F) |
| 1949 | -28.9 C (-20.0 F) |
| 1950 | -32.2 C (-26.0 F) |
| 1951 | -32.2 C (-26.0 F) |
| 1952 | -28.9 C (-20.0 F) |
| 1953 | -27.2 C (-17.0 F) |
| 1954 | -29.4 C (-20.9 F) |
| 1955 | -28.3 C (-18.9 F) |
| 1956 | -28.9 C (-20.0 F) |
| 1957 | -27.2 C (-17.0 F) |
| 1958 | -28.9 C (-20.0 F) |
| 1959 | -27.8 C (-18.0 F) |
| 1960 | -28.9 C (-20.0 F) |
| 1961 | -29.4 C (-20.9 F) |
| 1962 | -33.3 C (-27.9 F) |
| 1963 | -31.1 C (-24.0 F) |
| 1964 | -25.0 C (-13.0 F) |
| 1965 | -30.0 C (-22.0 F) |
| 1966 | -33.3 C (-27.9 F) |
| 1967 | -34.4 C (-29.9 F) |
| 1968 | -28.9 C (-20.0 F) |
| 1969 | -27.8 C (-18.0 F) |
| 1970 | -33.9 C (-29.0 F) |
| 1971 | -31.7 C (-25.1 F) |
| 1972 | -32.2 C (-26.0 F) |
| 1973 | -28.9 C (-20.0 F) |
| 1974 | -31.1 C (-24.0 F) |
| 1975 | -27.2 C (-17.0 F) |
| 1976 | -30.0 C (-22.0 F) |
| 1977 | -32.2 C (-26.0 F) |
| 1978 | -27.2 C (-17.0 F) |
| 1979 | -31.7 C (-25.1 F) |
| 1980 | -25.0 C (-13.0 F) |
| 1981 | -28.3 C (-18.9 F) |
| 1982 | -31.7 C (-25.1 F) |
| 1983 | -32.2 C (-26.0 F) |
| 1984 | -30.0 C (-22.0 F) |
| 1985 | -31.7 C (-25.1 F) |
| 1986 | -28.9 C (-20.0 F) |
| 1987 | -23.9 C (-11.0 F) |
| 1988 | -33.9 C (-29.0 F) |
| 1989 | -30.6 C (-23.1 F) |
| 1990 | -31.7 C (-25.1 F) |
| 1991 | -27.2 C (-17.0 F) |
| 1992 | -24.4 C (-11.9 F) |
| 1993 | -29.4 C (-20.9 F) |
| 1994 | -33.3 C (-27.9 F) |
| 1995 | -25.6 C (-14.1 F) |
| 1996 | -35.6 C (-32.1 F) |
| 1997 | -26.1 C (-15.0 F) |
| 1998 | -24.4 C (-11.9 F) |
| 1999 | -28.3 C (-18.9 F) |
| 2000 | -29.4 C (-20.9 F) |
| 2001 | -26.7 C (-16.1 F) |
| 2002 | -22.8 C (-9.0 F) |
| 2003 | -25.6 C (-14.1 F) |
| 2004 | -27.8 C (-18.0 F) |
| 2005 | -28.3 C (-18.9 F) |
| 2006 | -28.9 C (-20.0 F) |
| 2007 | -27.2 C (-17.0 F) |
| 2008 | -27.8 C (-18.0 F) |
| 2009 | -35.0 C (-31.0 F) |
| 2010 | -30.6 C (-23.1 F) |
| 2011 | -30.0 C (-22.0 F) |
| 2012 | -27.2 C (-17.0 F) |
| 2013 | -26.6 C (-15.9 F) |
| 2014 | -29.3 C (-20.7 F) |
| 2015 | -28.8 C (-19.8 F) |
| 2016 | -30.5 C (-22.9 F) |
| 2017 | -29.3 C (-20.7 F) |
| 2018 | -28.8 C (-19.8 F) |
| 2019 | -33.8 C (-28.8 F) |
| 2020 | -27.7 C (-17.9 F) |
| 2021 | -30.5 C (-22.9 F) |
| 2022 | -29.9 C (-21.8 F) |
| 2023 | -27.7 C (-17.9 F) |
| 2024 | -26.0 C (-14.8 F) |
| 2025 | -28.2 C (-18.8 F) |
| 2026 | -28.9 C (-20.0 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1948 | 41.1 mm (1.6 in) |
| 1949 | 87.1 mm (3.4 in) |
| 1950 | 41.9 mm (1.6 in) |
| 1951 | 118.9 mm (4.7 in) |
| 1952 | 62.0 mm (2.4 in) |
| 1953 | 46.0 mm (1.8 in) |
| 1954 | 160.8 mm (6.3 in) |
| 1955 | 55.4 mm (2.2 in) |
| 1956 | 52.1 mm (2.1 in) |
| 1957 | 28.7 mm (1.1 in) |
| 1958 | 73.2 mm (2.9 in) |
| 1959 | 59.9 mm (2.4 in) |
| 1960 | 28.4 mm (1.1 in) |
| 1961 | 43.4 mm (1.7 in) |
| 1962 | 81.5 mm (3.2 in) |
| 1963 | 62.5 mm (2.5 in) |
| 1964 | 82.0 mm (3.2 in) |
| 1965 | 93.7 mm (3.7 in) |
| 1966 | 68.3 mm (2.7 in) |
| 1967 | 67.1 mm (2.6 in) |
| 1968 | 68.1 mm (2.7 in) |
| 1969 | 67.6 mm (2.7 in) |
| 1970 | 45.7 mm (1.8 in) |
| 1971 | 59.2 mm (2.3 in) |
| 1972 | 50.8 mm (2.0 in) |
| 1973 | 42.4 mm (1.7 in) |
| 1974 | 50.8 mm (2.0 in) |
| 1975 | 59.7 mm (2.4 in) |
| 1976 | 31.8 mm (1.3 in) |
| 1977 | 70.4 mm (2.8 in) |
| 1978 | 132.1 mm (5.2 in) |
| 1979 | 86.4 mm (3.4 in) |
| 1980 | 93.5 mm (3.7 in) |
| 1981 | 90.9 mm (3.6 in) |
| 1982 | 69.9 mm (2.8 in) |
| 1983 | 116.1 mm (4.6 in) |
| 1984 | 100.1 mm (3.9 in) |
| 1985 | 84.3 mm (3.3 in) |
| 1986 | 69.9 mm (2.8 in) |
| 1987 | 42.9 mm (1.7 in) |
| 1988 | 62.7 mm (2.5 in) |
| 1989 | 25.4 mm (1.0 in) |
| 1990 | 101.1 mm (4.0 in) |
| 1991 | 58.2 mm (2.3 in) |
| 1992 | 56.6 mm (2.2 in) |
| 1993 | 45.7 mm (1.8 in) |
| 1994 | 61.0 mm (2.4 in) |
| 1995 | 79.2 mm (3.1 in) |
| 1996 | 51.6 mm (2.0 in) |
| 1997 | 50.0 mm (2.0 in) |
| 1998 | 52.6 mm (2.1 in) |
| 1999 | 79.5 mm (3.1 in) |
| 2000 | 76.5 mm (3.0 in) |
| 2001 | 61.5 mm (2.4 in) |
| 2002 | 52.1 mm (2.1 in) |
| 2003 | 55.6 mm (2.2 in) |
| 2004 | 116.6 mm (4.6 in) |
| 2005 | 69.6 mm (2.7 in) |
| 2006 | 64.5 mm (2.5 in) |
| 2007 | 121.7 mm (4.8 in) |
| 2008 | 124.7 mm (4.9 in) |
| 2009 | 49.8 mm (2.0 in) |
| 2010 | 39.6 mm (1.6 in) |
| 2011 | 42.4 mm (1.7 in) |
| 2012 | 39.6 mm (1.6 in) |
| 2013 | 54.9 mm (2.2 in) |
| 2014 | 62.5 mm (2.5 in) |
| 2015 | 104.9 mm (4.1 in) |
| 2016 | 70.1 mm (2.8 in) |
| 2017 | 39.9 mm (1.6 in) |
| 2018 | 57.7 mm (2.3 in) |
| 2019 | 62.5 mm (2.5 in) |
| 2020 | 61.7 mm (2.4 in) |
| 2021 | 80.0 mm (3.1 in) |
| 2022 | 66.5 mm (2.6 in) |
| 2023 | 40.1 mm (1.6 in) |
| 2024 | 43.7 mm (1.7 in) |
| 2025 | 63.0 mm (2.5 in) |
| 2026 | 59.2 mm (2.3 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1948 | 56.0 mm (2.2 in) |
| 1949 | 131.6 mm (5.2 in) |
| 1950 | 95.2 mm (3.7 in) |
| 1951 | 171.2 mm (6.7 in) |
| 1952 | 75.2 mm (3.0 in) |
| 1953 | 85.7 mm (3.4 in) |
| 1954 | 271.0 mm (10.7 in) |
| 1955 | 107.5 mm (4.2 in) |
| 1956 | 84.2 mm (3.3 in) |
| 1957 | 66.5 mm (2.6 in) |
| 1958 | 83.7 mm (3.3 in) |
| 1959 | 91.7 mm (3.6 in) |
| 1960 | 47.8 mm (1.9 in) |
| 1961 | 57.4 mm (2.3 in) |
| 1962 | 92.1 mm (3.6 in) |
| 1963 | 92.5 mm (3.6 in) |
| 1964 | 164.0 mm (6.5 in) |
| 1965 | 162.1 mm (6.4 in) |
| 1966 | 91.9 mm (3.6 in) |
| 1967 | 93.3 mm (3.7 in) |
| 1968 | 117.1 mm (4.6 in) |
| 1969 | 144.7 mm (5.7 in) |
| 1970 | 101.2 mm (4.0 in) |
| 1971 | 84.1 mm (3.3 in) |
| 1972 | 110.8 mm (4.4 in) |
| 1973 | 75.9 mm (3.0 in) |
| 1974 | 82.2 mm (3.2 in) |
| 1975 | 97.1 mm (3.8 in) |
| 1976 | 63.8 mm (2.5 in) |
| 1977 | 91.9 mm (3.6 in) |
| 1978 | 154.2 mm (6.1 in) |
| 1979 | 127.0 mm (5.0 in) |
| 1980 | 216.7 mm (8.5 in) |
| 1981 | 118.0 mm (4.6 in) |
| 1982 | 76.7 mm (3.0 in) |
| 1983 | 152.4 mm (6.0 in) |
| 1984 | 136.1 mm (5.4 in) |
| 1985 | 92.4 mm (3.6 in) |
| 1986 | 97.7 mm (3.8 in) |
| 1987 | 59.4 mm (2.3 in) |
| 1988 | 76.4 mm (3.0 in) |
| 1989 | 51.6 mm (2.0 in) |
| 1990 | 186.5 mm (7.3 in) |
| 1991 | 110.8 mm (4.4 in) |
| 1992 | 76.0 mm (3.0 in) |
| 1993 | 89.4 mm (3.5 in) |
| 1994 | 128.3 mm (5.1 in) |
| 1995 | 124.3 mm (4.9 in) |
| 1996 | 85.4 mm (3.4 in) |
| 1997 | 68.1 mm (2.7 in) |
| 1998 | 92.3 mm (3.6 in) |
| 1999 | 178.9 mm (7.0 in) |
| 2000 | 90.2 mm (3.6 in) |
| 2001 | 84.3 mm (3.3 in) |
| 2002 | 103.4 mm (4.1 in) |
| 2003 | 85.8 mm (3.4 in) |
| 2004 | 192.6 mm (7.6 in) |
| 2005 | 84.6 mm (3.3 in) |
| 2006 | 93.7 mm (3.7 in) |
| 2007 | 185.7 mm (7.3 in) |
| 2008 | 196.5 mm (7.7 in) |
| 2009 | 69.8 mm (2.7 in) |
| 2010 | 61.8 mm (2.4 in) |
| 2011 | 49.8 mm (2.0 in) |
| 2012 | 58.2 mm (2.3 in) |
| 2013 | 100.1 mm (3.9 in) |
| 2014 | 114.9 mm (4.5 in) |
| 2015 | 129.3 mm (5.1 in) |
| 2016 | 124.6 mm (4.9 in) |
| 2017 | 75.6 mm (3.0 in) |
| 2018 | 151.2 mm (6.0 in) |
| 2019 | 102.2 mm (4.0 in) |
| 2020 | 80.5 mm (3.2 in) |
| 2021 | 127.0 mm (5.0 in) |
| 2022 | 102.8 mm (4.0 in) |
| 2023 | 58.9 mm (2.3 in) |
| 2024 | 84.6 mm (3.3 in) |
| 2025 | 95.0 mm (3.7 in) |
| 2026 | 95.3 mm (3.8 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1948 | 33 days |
| 1949 | 34 days |
| 1950 | 31 days |
| 1951 | 21 days |
| 1952 | 58 days |
| 1953 | 24 days |
| 1954 | 30 days |
| 1955 | 31 days |
| 1956 | 34 days |
| 1957 | 23 days |
| 1958 | 24 days |
| 1959 | 24 days |
| 1960 | 33 days |
| 1961 | 17 days |
| 1962 | 27 days |
| 1963 | 29 days |
| 1964 | 38 days |
| 1965 | 21 days |
| 1966 | 24 days |
| 1967 | 17 days |
| 1968 | 29 days |
| 1969 | 21 days |
| 1970 | 40 days |
| 1971 | 17 days |
| 1972 | 31 days |
| 1973 | 16 days |
| 1974 | 18 days |
| 1975 | 25 days |
| 1976 | 44 days |
| 1977 | 19 days |
| 1978 | 22 days |
| 1979 | 30 days |
| 1980 | 30 days |
| 1981 | 25 days |
| 1982 | 24 days |
| 1983 | 18 days |
| 1984 | 16 days |
| 1985 | 16 days |
| 1986 | 32 days |
| 1987 | 29 days |
| 1988 | 23 days |
| 1989 | 18 days |
| 1990 | 20 days |
| 1991 | 37 days |
| 1992 | 21 days |
| 1993 | 18 days |
| 1994 | 26 days |
| 1995 | 25 days |
| 1996 | 24 days |
| 1997 | 18 days |
| 1998 | 35 days |
| 1999 | 24 days |
| 2000 | 24 days |
| 2001 | 27 days |
| 2002 | 35 days |
| 2003 | 27 days |
| 2004 | 19 days |
| 2005 | 15 days |
| 2006 | 25 days |
| 2007 | 29 days |
| 2008 | 15 days |
| 2009 | 30 days |
| 2010 | 27 days |
| 2011 | 20 days |
| 2012 | 24 days |
| 2013 | 22 days |
| 2014 | 26 days |
| 2015 | 24 days |
| 2016 | 22 days |
| 2017 | 39 days |
| 2018 | 23 days |
| 2019 | 18 days |
| 2020 | 28 days |
| 2021 | 18 days |
| 2022 | 18 days |
| 2023 | 24 days |
| 2024 | 39 days |
| 2025 | 40 days |
| 2026 | 17 days |
Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.
Frost Dates and Growing Season
78 years with a frostAcross 78 years with a frost, the median last spring frost at Mason City Muni AP falls on 3 May and the median first autumn frost on 2 October, which leaves a median of 155 days between them.
In 1996 to 2025 the median growing season was 153 days. That is 3 days fewer than in 1948 to 1977.
Fitted over all years, the growing season changes by -0.8 days per decade at this station.
| Measure | Median, all years | Earliest period (1948 to 1977) | Recent period (1996 to 2025) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 3 May | 6 May | 4 May | 2 days earlier | +0.5 days per decade |
| First autumn frost | 2 October | 3 October | 2 October | 1 day earlier | -0.4 days per decade |
| Growing days | 155 days | 156 days | 153 days | 3 days fewer | -0.8 days per decade |
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
78 years, 1948 to 2025A day with at least 61.8 mm (2.4 in) of rain is expected about once in 2 years. A day with at least 157.5 mm (6.2 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 61.8 mm (2.4 in) | |
| 5 years | 84.6 mm (3.3 in) | |
| 10 years | 100.8 mm (4.0 in) | |
| 25 years | 122.5 mm (4.8 in) | |
| 50 years | 139.7 mm (5.5 in) | |
| 100 years | 157.5 mm (6.2 in) | Longer than the 78 years of record |
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 78 years of values from 1948 to 2025.
A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.
The largest wettest-day totals in the fit: 160.8 mm (6.3 in) in 1954; 132.1 mm (5.2 in) in 1978; 124.7 mm (4.9 in) in 2008.
Station Changes
1 suspectedOne change was suspected in the annual mean temperature of Mason City Muni AP, at 1987. Each is measured against neighbouring stations.
- Relative to 5 neighbouring stations, the station's annual mean temperature from 1987 ran 0.3 C (0.5 F) lower than in the years before (likely change).
| Year | Shift (C) | Shift (F) | Strength | Neighbours |
|---|---|---|---|---|
| 1987 | -0.3 | -0.5 | likely | 5 |
Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.
Climate Twins
2011 to 2025 against 1961 to 1990Over 2011 to 2025, Mason City Muni AP had a mean temperature of 8.1 C (46.5 F) and 861.7 mm (33.9 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Colo (United States, 126 km away), Watertown Wwtp (United States, 372 km away) and Ft Atkinson Wwtp (United States, 364 km away).
| Twin station | Country | Distance away | Mean temperature, 1961-1990 | Rain a year, 1961-1990 | Climate difference |
|---|---|---|---|---|---|
| Colo | United States | 126 km (78 mi) | 8.3 C (47.0 F) | 866.4 mm (34.1 in) | 0.78 |
| Watertown Wwtp | United States | 372 km (231 mi) | 8.3 C (46.9 F) | 834.3 mm (32.8 in) | 0.80 |
| Ft Atkinson Wwtp | United States | 364 km (226 mi) | 8.2 C (46.7 F) | 830.5 mm (32.7 in) | 0.80 |
Twins are stations, not cities. A twin is one of the three stations at least 100 km away whose earlier climate is closest to this station's recent one, so a close match does not mean the two places look alike in other ways. A station move or a gap in a record can change that station's averages. The list describes past climate; it is not a forecast and does not say what caused any change. How twins are found, and a search for any station.
Download the Data
Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-15 (15 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2026-10-15).