Mauna Loa Slope Obs 39 Weather Records (USC00516198)
Record envelope, standing records and threshold days for Mauna Loa Slope Obs 39 (USC00516198), Hawaii, United States, with 72 years of record.
Key Facts for Mauna Loa Slope Obs 39
- Mauna Loa Slope Obs 39 (USC00516198) is a weather station in Hawaii, United States at 19.54 latitude and -155.58 longitude, 3,399 m (11,150 ft) above sea level.
- The station reports from 1955 to 2026, 72 years of record.
- 1,464 records set at Mauna Loa Slope Obs 39 still stand.
- Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
- Mauna Loa Slope Obs 39 set a daily record high minimum temperature of 8.9 C (48.0 F) on 26 July 2026.
About the Station
- Location: Hawaii, United States, 19.54 latitude, -155.58 longitude.
- Elevation: 3,399 m (11,150 ft).
- Period of record: 1955 to 2026, 72 years.
- Eligible elements: tmax, tmin, prcp.
Daily Record Envelope and 2026
2 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 19.4 C (66.9 F) | -7.2 C (19.0 F) | n/a | n/a |
| Feb | 20.6 C (69.1 F) | -7.8 C (18.0 F) | 15.0 C (59.0 F) | -1.1 C (30.0 F) |
| Mar | 18.9 C (66.0 F) | -6.7 C (19.9 F) | 16.1 C (61.0 F) | -1.1 C (30.0 F) |
| Apr | 19.4 C (66.9 F) | -5.0 C (23.0 F) | 13.3 C (55.9 F) | -0.6 C (30.9 F) |
| May | 20.0 C (68.0 F) | -2.8 C (27.0 F) | 15.6 C (60.1 F) | 0.0 C (32.0 F) |
| Jun | 21.7 C (71.1 F) | -2.2 C (28.0 F) | 16.7 C (62.1 F) | 3.3 C (37.9 F) |
| Jul | 21.1 C (70.0 F) | -3.3 C (26.1 F) | 18.3 C (64.9 F) | 3.3 C (37.9 F) |
| Aug | 20.6 C (69.1 F) | -2.2 C (28.0 F) | 16.7 C (62.1 F) | 4.4 C (39.9 F) |
| Sep | 25.6 C (78.1 F) | -1.7 C (28.9 F) | 12.8 C (55.0 F) | 3.9 C (39.0 F) |
| Oct | 20.0 C (68.0 F) | -2.8 C (27.0 F) | 16.1 C (61.0 F) | 2.8 C (37.0 F) |
| Nov | 18.3 C (64.9 F) | -3.9 C (25.0 F) | n/a | n/a |
| Dec | 19.4 C (66.9 F) | -6.1 C (21.0 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1955 | 66 |
| 1956 | 47 |
| 1957 | 29 |
| 1958 | 44 |
| 1959 | 44 |
| 1960 | 36 |
| 1961 | 25 |
| 1962 | 30 |
| 1963 | 37 |
| 1964 | 29 |
| 1965 | 44 |
| 1966 | 21 |
| 1967 | 21 |
| 1968 | 15 |
| 1969 | 15 |
| 1970 | 26 |
| 1971 | 39 |
| 1972 | 20 |
| 1973 | 23 |
| 1974 | 31 |
| 1975 | 20 |
| 1976 | 27 |
| 1977 | 12 |
| 1978 | 20 |
| 1979 | 15 |
| 1980 | 15 |
| 1981 | 25 |
| 1982 | 29 |
| 1983 | 37 |
| 1984 | 15 |
| 1985 | 20 |
| 1986 | 33 |
| 1987 | 40 |
| 1988 | 18 |
| 1989 | 22 |
| 1990 | 30 |
| 1991 | 34 |
| 1992 | 24 |
| 1993 | 17 |
| 1994 | 14 |
| 1995 | 14 |
| 1996 | 7 |
| 1997 | 13 |
| 1998 | 26 |
| 1999 | 12 |
| 2000 | 5 |
| 2001 | 14 |
| 2002 | 22 |
| 2003 | 15 |
| 2004 | 6 |
| 2005 | 5 |
| 2006 | 5 |
| 2007 | 9 |
| 2008 | 12 |
| 2009 | 5 |
| 2010 | 24 |
| 2011 | 20 |
| 2012 | 5 |
| 2013 | 4 |
| 2014 | 8 |
| 2015 | 13 |
| 2016 | 16 |
| 2017 | 16 |
| 2018 | 8 |
| 2019 | 16 |
| 2020 | 14 |
| 2021 | 4 |
| 2022 | 11 |
| 2023 | 6 |
| 2024 | 4 |
| 2025 | 12 |
| 2026 | 4 |
All-Time Record Progression
4 new records| Date | Kind | Detail |
|---|---|---|
| 1990-09-26 | Record high maximum temperature | Record high maximum temperature 25.6 C (78.1 F) |
| 1998-06-24 | Record high minimum temperature | Record high minimum temperature 11.1 C (52.0 F) |
| 2002-12-17 | Record high minimum temperature | Record high minimum temperature 11.7 C (53.1 F) |
| 2007-01-16 | Record high minimum temperature | Record high minimum temperature 12.8 C (55.0 F) |
Wettest Day of Each Month
Jan: 136.1 mm (5.4 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 136.1 mm (5.4 in) | 18 January 1959 |
| Feb | 72.6 mm (2.9 in) | 11 February 1982 |
| Mar | 50.3 mm (2.0 in) | 1 March 1985 |
| Apr | 113.0 mm (4.4 in) | 11 April 1986 |
| May | 49.5 mm (1.9 in) | 14 May 2002 |
| Jun | 25.1 mm (1.0 in) | 2 June 1989 |
| Jul | 51.1 mm (2.0 in) | 30 July 1997 |
| Aug | 99.1 mm (3.9 in) | 24 August 1957 |
| Sep | 74.9 mm (2.9 in) | 3 September 1957 |
| Oct | 59.2 mm (2.3 in) | 27 October 1974 |
| Nov | 96.0 mm (3.8 in) | 26 November 1967 |
| Dec | 114.3 mm (4.5 in) | 18 December 1987 |
Period of Record Coverage
1955 to 2026| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1955 | 358 | 98% | Yes |
| 1956 | 315 | 86% | No |
| 1957 | 340 | 93% | Yes |
| 1958 | 365 | 100% | Yes |
| 1959 | 336 | 92% | Yes |
| 1960 | 358 | 98% | Yes |
| 1961 | 364 | 100% | Yes |
| 1962 | 337 | 92% | Yes |
| 1963 | 363 | 99% | Yes |
| 1964 | 365 | 100% | Yes |
| 1965 | 365 | 100% | Yes |
| 1966 | 365 | 100% | Yes |
| 1967 | 365 | 100% | Yes |
| 1968 | 366 | 100% | Yes |
| 1969 | 356 | 98% | Yes |
| 1970 | 365 | 100% | Yes |
| 1971 | 365 | 100% | Yes |
| 1972 | 366 | 100% | Yes |
| 1973 | 362 | 99% | Yes |
| 1974 | 331 | 91% | Yes |
| 1975 | 356 | 98% | Yes |
| 1976 | 336 | 92% | Yes |
| 1977 | 360 | 99% | Yes |
| 1978 | 365 | 100% | Yes |
| 1979 | 348 | 95% | Yes |
| 1980 | 342 | 93% | Yes |
| 1981 | 365 | 100% | Yes |
| 1982 | 361 | 99% | Yes |
| 1983 | 358 | 98% | Yes |
| 1984 | 354 | 97% | Yes |
| 1985 | 365 | 100% | Yes |
| 1986 | 364 | 100% | Yes |
| 1987 | 337 | 92% | Yes |
| 1988 | 357 | 98% | Yes |
| 1989 | 364 | 100% | Yes |
| 1990 | 362 | 99% | Yes |
| 1991 | 360 | 99% | Yes |
| 1992 | 328 | 90% | No |
| 1993 | 249 | 68% | No |
| 1994 | 250 | 68% | No |
| 1995 | 248 | 68% | No |
| 1996 | 250 | 68% | No |
| 1997 | 245 | 67% | No |
| 1998 | 252 | 69% | No |
| 1999 | 249 | 68% | No |
| 2000 | 250 | 68% | No |
| 2001 | 250 | 68% | No |
| 2002 | 249 | 68% | No |
| 2003 | 249 | 68% | No |
| 2004 | 247 | 67% | No |
| 2005 | 249 | 68% | No |
| 2006 | 250 | 68% | No |
| 2007 | 236 | 65% | No |
| 2008 | 246 | 67% | No |
| 2009 | 251 | 69% | No |
| 2010 | 249 | 68% | No |
| 2011 | 252 | 69% | No |
| 2012 | 241 | 66% | No |
| 2013 | 246 | 67% | No |
| 2014 | 243 | 67% | No |
| 2015 | 247 | 68% | No |
| 2016 | 247 | 67% | No |
| 2017 | 247 | 68% | No |
| 2018 | 243 | 67% | No |
| 2019 | 246 | 67% | No |
| 2020 | 245 | 67% | No |
| 2021 | 235 | 64% | No |
| 2022 | 233 | 64% | No |
| 2023 | 15 | 4% | No |
| 2024 | 28 | 8% | No |
| 2025 | 273 | 75% | No |
| 2026 | 92 | 25% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 26 July 2026 | Mauna Loa Slope Obs 39, US | daily high min | 8.9 C (48.0 F) | 2.2 C (4.0 F) | 43 years | 30 of 100 (Routine) |
| 26 July 2026 | Mauna Loa Slope Obs 39, US | daily high max | 18.3 C (64.9 F) | 0.5 C (0.9 F) | 67 years | 29 of 100 (Routine) |
| 25 July 2026 | Mauna Loa Slope Obs 39, US | daily high min | 8.9 C (48.0 F) | 1.7 C (3.1 F) | 39 years | 26 of 100 (Routine) |
| 25 July 2026 | Mauna Loa Slope Obs 39, US | daily high max | 18.3 C (64.9 F) | 0.5 C (0.9 F) | 20 years | 15 of 100 (Routine) |
| 18 May 2026 | Mauna Loa Slope Obs 39, US | daily rain | 20.6 mm (0.8 in) | 5.4 mm (0.21 in) | 52 years | 20 of 100 (Routine) |
| 30 December 2025 | Mauna Loa Slope Obs 39, US | daily high min (Tie) | 5.0 C (41.0 F) | tie | 32 years | 4 of 100 (Routine) |
| 16 December 2025 | Mauna Loa Slope Obs 39, US | daily high min | 6.1 C (43.0 F) | 1.1 C (2.0 F) | 39 years | 23 of 100 (Routine) |
| 16 December 2025 | Mauna Loa Slope Obs 39, US | daily high max (Tie) | 16.1 C (61.0 F) | tie | 46 years | 5 of 100 (Routine) |
| 26 October 2025 | Mauna Loa Slope Obs 39, US | daily high min (Tie) | 5.6 C (42.1 F) | tie | 59 years | 6 of 100 (Routine) |
| 3 September 2025 | Mauna Loa Slope Obs 39, US | daily high max (Tie) | 17.8 C (64.0 F) | tie | 36 years | 4 of 100 (Routine) |
| 5 July 2025 | Mauna Loa Slope Obs 39, US | daily high min | 8.9 C (48.0 F) | 1.1 C (2.0 F) | 44 years | 25 of 100 (Routine) |
| 5 July 2025 | Mauna Loa Slope Obs 39, US | daily high max | 20.6 C (69.1 F) | 0.6 C (1.1 F) | 14 years | 13 of 100 (Routine) |
| 4 July 2025 | Mauna Loa Slope Obs 39, US | daily high min | 7.8 C (46.0 F) | 0.6 C (1.1 F) | 44 years | 23 of 100 (Routine) |
| 4 July 2025 | Mauna Loa Slope Obs 39, US | daily high max (Tie) | 18.3 C (64.9 F) | tie | 63 years | 6 of 100 (Routine) |
| 1 June 2025 | Mauna Loa Slope Obs 39, US | daily high max (Tie) | 18.9 C (66.0 F) | tie | 67 years | 6 of 100 (Routine) |
| 1 June 2025 | Mauna Loa Slope Obs 39, US | daily high min (Tie) | 8.3 C (46.9 F) | tie | 3 years | 1 of 100 (Routine) |
| 18 April 2025 | Mauna Loa Slope Obs 39, US | daily low max | 7.2 C (45.0 F) | 0.6 C (1.1 F) | 63 years | 27 of 100 (Routine) |
| 2 April 2025 | Mauna Loa Slope Obs 39, US | daily high min | 6.1 C (43.0 F) | 1.1 C (2.0 F) | 34 years | 22 of 100 (Routine) |
| 1 April 2025 | Mauna Loa Slope Obs 39, US | daily high min | 6.7 C (44.1 F) | 2.8 C (5.0 F) | 62 years | 38 of 100 (Notable) |
| 1 April 2025 | Mauna Loa Slope Obs 39, US | daily high max | 17.8 C (64.0 F) | 2.2 C (4.0 F) | 66 years | 34 of 100 (Routine) |
Climate Trend
29 complete years, 1955 to 1991| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1955 | 6.0 C | -1.13 C |
| 1957 | 6.8 C | -0.27 C |
| 1958 | 8.0 C | +0.84 C |
| 1960 | 6.9 C | -0.19 C |
| 1961 | 7.0 C | -0.15 C |
| 1963 | 6.6 C | -0.54 C |
| 1964 | 6.4 C | -0.71 C |
| 1965 | 6.3 C | -0.84 C |
| 1966 | 7.4 C | +0.31 C |
| 1967 | 6.6 C | -0.55 C |
| 1968 | 7.1 C | -0.01 C |
| 1969 | 7.2 C | +0.06 C |
| 1970 | 6.5 C | -0.66 C |
| 1971 | 6.0 C | -1.10 C |
| 1972 | 6.5 C | -0.60 C |
| 1973 | 7.3 C | +0.16 C |
| 1977 | 7.2 C | +0.07 C |
| 1978 | 6.5 C | -0.59 C |
| 1979 | 6.8 C | -0.36 C |
| 1981 | 7.9 C | +0.82 C |
| 1982 | 7.4 C | +0.33 C |
| 1983 | 8.3 C | +1.19 C |
| 1984 | 7.7 C | +0.61 C |
| 1985 | 7.6 C | +0.51 C |
| 1986 | 8.7 C | +1.60 C |
| 1988 | 7.5 C | +0.38 C |
| 1989 | 6.8 C | -0.33 C |
| 1990 | 7.6 C | +0.45 C |
| 1991 | 7.9 C | +0.83 C |
This station does not have enough complete years (30 are needed) to fit a temperature trend.
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
1955 to 2026| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 25.6 C (78.1 F) | 1990 | 19.2 C (66.5 F) | 72 |
| Coldest night (TNn) | -7.8 C (18.0 F) | 1962 | -4.4 C (24.1 F) | 72 |
| Wettest day (Rx1day) | 136.1 mm (5.4 in) | 1959 | 37.6 mm (1.5 in) | 71 |
| Wettest five days (Rx5day) | 226.8 mm (8.9 in) | 1986 | 54.1 mm (2.1 in) | 61 |
| Longest dry spell (CDD) | 108 days | 1998 | 39 days | 70 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1955 | 18.3 C (64.9 F) |
| 1956 | 19.4 C (66.9 F) |
| 1957 | 19.4 C (66.9 F) |
| 1958 | 21.1 C (70.0 F) |
| 1959 | 20.0 C (68.0 F) |
| 1960 | 19.4 C (66.9 F) |
| 1961 | 18.9 C (66.0 F) |
| 1962 | 19.4 C (66.9 F) |
| 1963 | 19.4 C (66.9 F) |
| 1964 | 18.3 C (64.9 F) |
| 1965 | 17.8 C (64.0 F) |
| 1966 | 20.0 C (68.0 F) |
| 1967 | 17.8 C (64.0 F) |
| 1968 | 18.3 C (64.9 F) |
| 1969 | 18.9 C (66.0 F) |
| 1970 | 18.9 C (66.0 F) |
| 1971 | 17.2 C (63.0 F) |
| 1972 | 18.9 C (66.0 F) |
| 1973 | 18.9 C (66.0 F) |
| 1974 | 16.7 C (62.1 F) |
| 1975 | 17.8 C (64.0 F) |
| 1976 | 16.1 C (61.0 F) |
| 1977 | 17.2 C (63.0 F) |
| 1978 | 16.7 C (62.1 F) |
| 1979 | 17.2 C (63.0 F) |
| 1980 | 18.9 C (66.0 F) |
| 1981 | 20.0 C (68.0 F) |
| 1982 | 17.8 C (64.0 F) |
| 1983 | 18.9 C (66.0 F) |
| 1984 | 18.9 C (66.0 F) |
| 1985 | 18.3 C (64.9 F) |
| 1986 | 18.3 C (64.9 F) |
| 1987 | 17.8 C (64.0 F) |
| 1988 | 18.3 C (64.9 F) |
| 1989 | 18.9 C (66.0 F) |
| 1990 | 25.6 C (78.1 F) |
| 1991 | 20.0 C (68.0 F) |
| 1992 | 18.9 C (66.0 F) |
| 1993 | 20.0 C (68.0 F) |
| 1994 | 18.9 C (66.0 F) |
| 1995 | 19.4 C (66.9 F) |
| 1996 | 18.9 C (66.0 F) |
| 1997 | 20.0 C (68.0 F) |
| 1998 | 21.7 C (71.1 F) |
| 1999 | 20.0 C (68.0 F) |
| 2000 | 19.4 C (66.9 F) |
| 2001 | 21.1 C (70.0 F) |
| 2002 | 20.0 C (68.0 F) |
| 2003 | 20.6 C (69.1 F) |
| 2004 | 18.9 C (66.0 F) |
| 2005 | 18.9 C (66.0 F) |
| 2006 | 19.4 C (66.9 F) |
| 2007 | 20.0 C (68.0 F) |
| 2008 | 18.9 C (66.0 F) |
| 2009 | 19.4 C (66.9 F) |
| 2010 | 19.4 C (66.9 F) |
| 2011 | 20.0 C (68.0 F) |
| 2012 | 18.3 C (64.9 F) |
| 2013 | 20.0 C (68.0 F) |
| 2014 | 18.9 C (66.0 F) |
| 2015 | 18.9 C (66.0 F) |
| 2016 | 20.0 C (68.0 F) |
| 2017 | 21.1 C (70.0 F) |
| 2018 | 19.4 C (66.9 F) |
| 2019 | 19.4 C (66.9 F) |
| 2020 | 20.0 C (68.0 F) |
| 2021 | 20.6 C (69.1 F) |
| 2022 | 20.0 C (68.0 F) |
| 2023 | 20.0 C (68.0 F) |
| 2024 | 20.6 C (69.1 F) |
| 2025 | 20.6 C (69.1 F) |
| 2026 | 18.3 C (64.9 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1955 | -6.7 C (19.9 F) |
| 1956 | -6.7 C (19.9 F) |
| 1957 | -5.6 C (21.9 F) |
| 1958 | -5.6 C (21.9 F) |
| 1959 | -5.6 C (21.9 F) |
| 1960 | -5.0 C (23.0 F) |
| 1961 | -3.3 C (26.1 F) |
| 1962 | -7.8 C (18.0 F) |
| 1963 | -5.0 C (23.0 F) |
| 1964 | -6.1 C (21.0 F) |
| 1965 | -6.1 C (21.0 F) |
| 1966 | -4.4 C (24.1 F) |
| 1967 | -5.6 C (21.9 F) |
| 1968 | -3.9 C (25.0 F) |
| 1969 | -5.6 C (21.9 F) |
| 1970 | -5.0 C (23.0 F) |
| 1971 | -7.2 C (19.0 F) |
| 1972 | -4.4 C (24.1 F) |
| 1973 | -4.4 C (24.1 F) |
| 1974 | -3.3 C (26.1 F) |
| 1975 | -4.4 C (24.1 F) |
| 1976 | -5.0 C (23.0 F) |
| 1977 | -3.9 C (25.0 F) |
| 1978 | -5.0 C (23.0 F) |
| 1979 | -4.4 C (24.1 F) |
| 1980 | -2.8 C (27.0 F) |
| 1981 | -2.8 C (27.0 F) |
| 1982 | -3.9 C (25.0 F) |
| 1983 | -2.2 C (28.0 F) |
| 1984 | -2.8 C (27.0 F) |
| 1985 | -2.2 C (28.0 F) |
| 1986 | -2.8 C (27.0 F) |
| 1987 | -2.2 C (28.0 F) |
| 1988 | -5.0 C (23.0 F) |
| 1989 | -4.4 C (24.1 F) |
| 1990 | -5.0 C (23.0 F) |
| 1991 | -2.2 C (28.0 F) |
| 1992 | -6.1 C (21.0 F) |
| 1993 | -5.0 C (23.0 F) |
| 1994 | -2.8 C (27.0 F) |
| 1995 | -2.2 C (28.0 F) |
| 1996 | -2.8 C (27.0 F) |
| 1997 | -3.3 C (26.1 F) |
| 1998 | -3.9 C (25.0 F) |
| 1999 | -3.9 C (25.0 F) |
| 2000 | -3.9 C (25.0 F) |
| 2001 | -2.8 C (27.0 F) |
| 2002 | -4.4 C (24.1 F) |
| 2003 | -2.2 C (28.0 F) |
| 2004 | -3.3 C (26.1 F) |
| 2005 | -3.3 C (26.1 F) |
| 2006 | -3.9 C (25.0 F) |
| 2007 | -6.1 C (21.0 F) |
| 2008 | -5.0 C (23.0 F) |
| 2009 | -5.6 C (21.9 F) |
| 2010 | -3.9 C (25.0 F) |
| 2011 | -5.6 C (21.9 F) |
| 2012 | -5.0 C (23.0 F) |
| 2013 | -5.0 C (23.0 F) |
| 2014 | -6.1 C (21.0 F) |
| 2015 | -2.2 C (28.0 F) |
| 2016 | -1.7 C (28.9 F) |
| 2017 | -5.6 C (21.9 F) |
| 2018 | -2.8 C (27.0 F) |
| 2019 | -6.7 C (19.9 F) |
| 2020 | -5.6 C (21.9 F) |
| 2021 | -4.4 C (24.1 F) |
| 2022 | -5.6 C (21.9 F) |
| 2023 | -0.6 C (30.9 F) |
| 2024 | -3.3 C (26.1 F) |
| 2025 | -1.7 C (28.9 F) |
| 2026 | -1.1 C (30.0 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1955 | 8.9 mm (0.35 in) |
| 1956 | 1.5 mm (0.06 in) |
| 1957 | 99.1 mm (3.9 in) |
| 1958 | 40.6 mm (1.6 in) |
| 1959 | 136.1 mm (5.4 in) |
| 1960 | 40.6 mm (1.6 in) |
| 1961 | 30.7 mm (1.2 in) |
| 1962 | 19.1 mm (0.8 in) |
| 1963 | 63.5 mm (2.5 in) |
| 1964 | 26.2 mm (1.0 in) |
| 1965 | 48.3 mm (1.9 in) |
| 1966 | 61.5 mm (2.4 in) |
| 1967 | 96.0 mm (3.8 in) |
| 1968 | 94.2 mm (3.7 in) |
| 1969 | 29.7 mm (1.2 in) |
| 1970 | 39.6 mm (1.6 in) |
| 1971 | 56.1 mm (2.2 in) |
| 1972 | 79.5 mm (3.1 in) |
| 1973 | 74.2 mm (2.9 in) |
| 1974 | 59.2 mm (2.3 in) |
| 1975 | 83.6 mm (3.3 in) |
| 1976 | 61.7 mm (2.4 in) |
| 1977 | 32.0 mm (1.3 in) |
| 1978 | 25.9 mm (1.0 in) |
| 1979 | 22.1 mm (0.9 in) |
| 1980 | 108.5 mm (4.3 in) |
| 1981 | 32.5 mm (1.3 in) |
| 1982 | 72.6 mm (2.9 in) |
| 1983 | 18.5 mm (0.7 in) |
| 1984 | 16.3 mm (0.6 in) |
| 1985 | 50.3 mm (2.0 in) |
| 1986 | 113.0 mm (4.4 in) |
| 1987 | 114.3 mm (4.5 in) |
| 1988 | 70.1 mm (2.8 in) |
| 1989 | 44.2 mm (1.7 in) |
| 1990 | 75.9 mm (3.0 in) |
| 1991 | 23.6 mm (0.9 in) |
| 1992 | 28.4 mm (1.1 in) |
| 1993 | 16.8 mm (0.7 in) |
| 1994 | 26.7 mm (1.1 in) |
| 1995 | 31.0 mm (1.2 in) |
| 1996 | 28.4 mm (1.1 in) |
| 1997 | 51.1 mm (2.0 in) |
| 1998 | 14.2 mm (0.6 in) |
| 1999 | 28.2 mm (1.1 in) |
| 2000 | 41.1 mm (1.6 in) |
| 2001 | 78.7 mm (3.1 in) |
| 2002 | 49.5 mm (1.9 in) |
| 2003 | 29.2 mm (1.1 in) |
| 2004 | 38.4 mm (1.5 in) |
| 2005 | 39.4 mm (1.6 in) |
| 2006 | 37.6 mm (1.5 in) |
| 2007 | 25.9 mm (1.0 in) |
| 2008 | 71.6 mm (2.8 in) |
| 2009 | 26.4 mm (1.0 in) |
| 2010 | 17.3 mm (0.7 in) |
| 2011 | 24.9 mm (1.0 in) |
| 2012 | 19.8 mm (0.8 in) |
| 2013 | 12.7 mm (0.5 in) |
| 2014 | 26.4 mm (1.0 in) |
| 2015 | 35.1 mm (1.4 in) |
| 2016 | 24.4 mm (1.0 in) |
| 2017 | 31.0 mm (1.2 in) |
| 2018 | 40.1 mm (1.6 in) |
| 2019 | 55.4 mm (2.2 in) |
| 2020 | 34.5 mm (1.4 in) |
| 2021 | 57.2 mm (2.3 in) |
| 2022 | 29.5 mm (1.2 in) |
| 2023 | 44.5 mm (1.8 in) |
| 2024 | 0.0 mm (0.00 in) |
| 2025 | n/a |
| 2026 | 20.6 mm (0.8 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1955 | 16.8 mm (0.7 in) |
| 1956 | 1.5 mm (0.06 in) |
| 1957 | 131.7 mm (5.2 in) |
| 1958 | 63.3 mm (2.5 in) |
| 1959 | 158.4 mm (6.2 in) |
| 1960 | 47.9 mm (1.9 in) |
| 1961 | 57.9 mm (2.3 in) |
| 1962 | 46.0 mm (1.8 in) |
| 1963 | 142.2 mm (5.6 in) |
| 1964 | 58.3 mm (2.3 in) |
| 1965 | 103.8 mm (4.1 in) |
| 1966 | 83.7 mm (3.3 in) |
| 1967 | 108.5 mm (4.3 in) |
| 1968 | 141.6 mm (5.6 in) |
| 1969 | 112.5 mm (4.4 in) |
| 1970 | 66.9 mm (2.6 in) |
| 1971 | 66.2 mm (2.6 in) |
| 1972 | 98.3 mm (3.9 in) |
| 1973 | 115.1 mm (4.5 in) |
| 1974 | 120.7 mm (4.8 in) |
| 1975 | 100.4 mm (4.0 in) |
| 1976 | 123.7 mm (4.9 in) |
| 1977 | 40.9 mm (1.6 in) |
| 1978 | 15.8 mm (0.6 in) |
| 1979 | 22.1 mm (0.9 in) |
| 1980 | 29.2 mm (1.1 in) |
| 1981 | 61.5 mm (2.4 in) |
| 1982 | 35.3 mm (1.4 in) |
| 1983 | 27.4 mm (1.1 in) |
| 1984 | 17.3 mm (0.7 in) |
| 1985 | 16.8 mm (0.7 in) |
| 1986 | 226.8 mm (8.9 in) |
| 1987 | 49.1 mm (1.9 in) |
| 1988 | 70.1 mm (2.8 in) |
| 1989 | 63.0 mm (2.5 in) |
| 1990 | 55.0 mm (2.2 in) |
| 1991 | 24.9 mm (1.0 in) |
| 1992 | 66.1 mm (2.6 in) |
| 1993 | 20.3 mm (0.8 in) |
| 1994 | 84.1 mm (3.3 in) |
| 1995 | 31.0 mm (1.2 in) |
| 1996 | 49.0 mm (1.9 in) |
| 1997 | 56.7 mm (2.2 in) |
| 1998 | 14.2 mm (0.6 in) |
| 1999 | 51.6 mm (2.0 in) |
| 2000 | 41.4 mm (1.6 in) |
| 2001 | 110.7 mm (4.4 in) |
| 2002 | 82.8 mm (3.3 in) |
| 2003 | 29.2 mm (1.1 in) |
| 2004 | 51.8 mm (2.0 in) |
| 2005 | 56.4 mm (2.2 in) |
| 2006 | 54.1 mm (2.1 in) |
| 2007 | 28.9 mm (1.1 in) |
| 2008 | 71.6 mm (2.8 in) |
| 2009 | 39.7 mm (1.6 in) |
| 2010 | 3.6 mm (0.14 in) |
| 2011 | 33.6 mm (1.3 in) |
| 2012 | 2.5 mm (0.10 in) |
| 2013 | n/a |
| 2014 | n/a |
| 2015 | 0.0 mm (0.00 in) |
| 2016 | n/a |
| 2017 | n/a |
| 2018 | 12.2 mm (0.5 in) |
| 2019 | n/a |
| 2020 | n/a |
| 2021 | n/a |
| 2022 | 10.2 mm (0.4 in) |
| 2023 | n/a |
| 2024 | n/a |
| 2025 | n/a |
| 2026 | n/a |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1955 | 50 days |
| 1956 | 31 days |
| 1957 | 37 days |
| 1958 | 59 days |
| 1959 | 67 days |
| 1960 | 54 days |
| 1961 | 39 days |
| 1962 | 44 days |
| 1963 | 53 days |
| 1964 | 37 days |
| 1965 | 26 days |
| 1966 | 59 days |
| 1967 | 27 days |
| 1968 | 22 days |
| 1969 | 69 days |
| 1970 | 85 days |
| 1971 | 40 days |
| 1972 | 33 days |
| 1973 | 68 days |
| 1974 | 34 days |
| 1975 | 82 days |
| 1976 | 75 days |
| 1977 | 61 days |
| 1978 | 42 days |
| 1979 | 32 days |
| 1980 | 37 days |
| 1981 | 71 days |
| 1982 | 22 days |
| 1983 | 66 days |
| 1984 | 48 days |
| 1985 | 37 days |
| 1986 | 43 days |
| 1987 | 34 days |
| 1988 | 52 days |
| 1989 | 43 days |
| 1990 | 75 days |
| 1991 | 55 days |
| 1992 | 106 days |
| 1993 | 74 days |
| 1994 | 32 days |
| 1995 | 49 days |
| 1996 | 58 days |
| 1997 | 34 days |
| 1998 | 108 days |
| 1999 | 48 days |
| 2000 | 59 days |
| 2001 | 40 days |
| 2002 | 39 days |
| 2003 | 38 days |
| 2004 | 31 days |
| 2005 | 41 days |
| 2006 | 39 days |
| 2007 | 48 days |
| 2008 | 35 days |
| 2009 | 32 days |
| 2010 | 88 days |
| 2011 | 33 days |
| 2012 | 18 days |
| 2013 | 4 days |
| 2014 | 4 days |
| 2015 | 5 days |
| 2016 | 4 days |
| 2017 | 4 days |
| 2018 | 4 days |
| 2019 | 4 days |
| 2020 | 4 days |
| 2021 | 4 days |
| 2022 | 5 days |
| 2023 | n/a |
| 2024 | 1 day |
| 2025 | n/a |
| 2026 | 3 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
29 years with a frostAcross 29 years with a frost, the median last spring frost at Mauna Loa Slope Obs 39 falls on 28 May and the median first autumn frost on 21 October, which leaves a median of 145 days between them.
Fitted over all years, the growing season changes by +57.3 days per decade at this station.
| Measure | Median, all years | Earliest period | Recent period (1955 to 1991) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 28 May | n/a | 28 May | n/a | -12.4 days per decade |
| First autumn frost | 21 October | n/a | 21 October | n/a | +44.9 days per decade |
| Growing days | 145 days | n/a | 145 days | n/a | +57.3 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.
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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2026-10-12).