Natl Arboretum Dc Weather Records (USC00186350)
Record envelope, standing records and threshold days for Natl Arboretum Dc (USC00186350), Maryland, United States, with 79 years of record.
Key Facts for Natl Arboretum Dc
- Natl Arboretum Dc (USC00186350) is a weather station in Maryland, United States at 38.91 latitude and -76.97 longitude, 15 m (50 ft) above sea level.
- The station reports from 1948 to 2026, 79 years of record.
- 1,464 records set at Natl Arboretum Dc still stand.
- Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
- Natl Arboretum Dc set a daily record precipitation of 40.4 mm (1.6 in) on 3 August 2026.
About the Station
- Location: Maryland, United States, 38.91 latitude, -76.97 longitude.
- Elevation: 15 m (50 ft).
- Period of record: 1948 to 2026, 79 years.
- Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
14 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 26.7 C (80.1 F) | -23.3 C (-9.9 F) | 17.2 C (63.0 F) | -12.2 C (10.0 F) |
| Feb | 27.8 C (82.0 F) | -18.3 C (-0.9 F) | 14.4 C (57.9 F) | -11.1 C (12.0 F) |
| Mar | 32.2 C (90.0 F) | -13.9 C (7.0 F) | 30.0 C (86.0 F) | -2.8 C (27.0 F) |
| Apr | 34.4 C (93.9 F) | -7.8 C (18.0 F) | 33.3 C (91.9 F) | -0.6 C (30.9 F) |
| May | 38.3 C (100.9 F) | -3.9 C (25.0 F) | 35.6 C (96.1 F) | 5.0 C (41.0 F) |
| Jun | 39.4 C (102.9 F) | 5.6 C (42.1 F) | 33.9 C (93.0 F) | 12.2 C (54.0 F) |
| Jul | 41.1 C (106.0 F) | 8.3 C (46.9 F) | 39.4 C (102.9 F) | 15.6 C (60.1 F) |
| Aug | 40.0 C (104.0 F) | 5.6 C (42.1 F) | 32.8 C (91.0 F) | 23.3 C (73.9 F) |
| Sep | 38.9 C (102.0 F) | 1.1 C (34.0 F) | n/a | n/a |
| Oct | 34.4 C (93.9 F) | -6.7 C (19.9 F) | n/a | n/a |
| Nov | 30.6 C (87.1 F) | -12.2 C (10.0 F) | n/a | n/a |
| Dec | 27.2 C (81.0 F) | -17.8 C (0.0 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1948 | 7 |
| 1949 | 22 |
| 1950 | 30 |
| 1951 | 29 |
| 1952 | 17 |
| 1953 | 10 |
| 1954 | 36 |
| 1955 | 17 |
| 1956 | 18 |
| 1957 | 25 |
| 1958 | 13 |
| 1959 | 21 |
| 1960 | 23 |
| 1961 | 19 |
| 1962 | 14 |
| 1963 | 26 |
| 1964 | 24 |
| 1965 | 13 |
| 1966 | 24 |
| 1967 | 24 |
| 1968 | 15 |
| 1969 | 11 |
| 1970 | 14 |
| 1971 | 19 |
| 1972 | 21 |
| 1973 | 16 |
| 1974 | 23 |
| 1975 | 14 |
| 1976 | 27 |
| 1977 | 17 |
| 1978 | 15 |
| 1979 | 39 |
| 1980 | 6 |
| 1981 | 13 |
| 1982 | 22 |
| 1983 | 23 |
| 1984 | 27 |
| 1985 | 15 |
| 1986 | 15 |
| 1987 | 14 |
| 1988 | 41 |
| 1989 | 33 |
| 1990 | 18 |
| 1991 | 37 |
| 1992 | 17 |
| 1993 | 13 |
| 1994 | 11 |
| 1995 | 6 |
| 1996 | 25 |
| 1997 | 15 |
| 1998 | 26 |
| 1999 | 21 |
| 2000 | 21 |
| 2001 | 19 |
| 2002 | 4 |
| 2003 | 11 |
| 2004 | 13 |
| 2005 | 11 |
| 2006 | 13 |
| 2007 | 13 |
| 2008 | 9 |
| 2009 | 14 |
| 2010 | 17 |
| 2011 | 25 |
| 2012 | 22 |
| 2013 | 15 |
| 2014 | 20 |
| 2015 | 29 |
| 2016 | 22 |
| 2017 | 23 |
| 2018 | 36 |
| 2019 | 4 |
| 2020 | 6 |
| 2021 | 14 |
| 2022 | 11 |
| 2023 | 7 |
| 2024 | 12 |
| 2025 | 16 |
| 2026 | 16 |
All-Time Record Progression
10 new records| Date | Kind | Detail |
|---|---|---|
| 1979-02-13 | Record snow depth | Record snow depth 25.4 cm (10.0 in) |
| 1979-02-19 | Record snow depth | Record snow depth 45.7 cm (18.0 in) |
| 1979-02-20 | Record snow depth | Record snow depth 61.0 cm (24.0 in) |
| 1982-01-11 | Record low maximum temperature | Record low maximum temperature -12.8 C (9.0 F) |
| 1982-01-11 | Record low minimum temperature | Record low minimum temperature -20.6 C (-5.1 F) |
| 1982-01-17 | Record low minimum temperature | Record low minimum temperature -23.3 C (-9.9 F) |
| 2006-06-26 | Record daily precipitation | Record daily precipitation 187.2 mm (7.4 in) |
| 2011-07-23 | Record high maximum temperature | Record high maximum temperature 40.6 C (105.1 F) |
| 2011-07-30 | Record high maximum temperature | Record high maximum temperature 41.1 C (106.0 F) |
| 2012-07-08 | Record high minimum temperature | Record high minimum temperature 28.3 C (82.9 F) |
Wettest Day of Each Month
Jun: 187.2 mm (7.4 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 61.7 mm (2.4 in) | 1 January 1976 |
| Feb | 61.7 mm (2.4 in) | 23 February 2003 |
| Mar | 66.3 mm (2.6 in) | 29 March 1984 |
| Apr | 73.2 mm (2.9 in) | 14 April 1970 |
| May | 92.7 mm (3.6 in) | 12 May 2008 |
| Jun | 187.2 mm (7.4 in) | 26 June 2006 |
| Jul | 121.9 mm (4.8 in) | 29 July 2017 |
| Aug | 149.4 mm (5.9 in) | 13 August 1955 |
| Sep | 157.0 mm (6.2 in) | 6 September 1979 |
| Oct | 134.6 mm (5.3 in) | 14 October 1955 |
| Nov | 73.9 mm (2.9 in) | 9 November 1996 |
| Dec | 72.1 mm (2.8 in) | 2 December 1974 |
Period of Record Coverage
1948 to 2026| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1948 | 153 | 42% | No |
| 1949 | 365 | 100% | Yes |
| 1950 | 360 | 99% | Yes |
| 1951 | 357 | 98% | Yes |
| 1952 | 321 | 88% | No |
| 1953 | 238 | 65% | No |
| 1954 | 338 | 93% | Yes |
| 1955 | 363 | 99% | Yes |
| 1956 | 361 | 99% | Yes |
| 1957 | 361 | 99% | Yes |
| 1958 | 360 | 99% | Yes |
| 1959 | 361 | 99% | Yes |
| 1960 | 360 | 98% | Yes |
| 1961 | 365 | 100% | Yes |
| 1962 | 361 | 99% | Yes |
| 1963 | 364 | 100% | Yes |
| 1964 | 366 | 100% | Yes |
| 1965 | 363 | 99% | Yes |
| 1966 | 364 | 100% | Yes |
| 1967 | 365 | 100% | Yes |
| 1968 | 364 | 99% | Yes |
| 1969 | 364 | 100% | Yes |
| 1970 | 365 | 100% | Yes |
| 1971 | 364 | 100% | Yes |
| 1972 | 366 | 100% | Yes |
| 1973 | 365 | 100% | Yes |
| 1974 | 363 | 99% | Yes |
| 1975 | 359 | 98% | Yes |
| 1976 | 363 | 99% | Yes |
| 1977 | 363 | 99% | Yes |
| 1978 | 363 | 99% | Yes |
| 1979 | 363 | 99% | Yes |
| 1980 | 329 | 90% | No |
| 1981 | 356 | 98% | Yes |
| 1982 | 362 | 99% | Yes |
| 1983 | 362 | 99% | Yes |
| 1984 | 363 | 99% | Yes |
| 1985 | 358 | 98% | Yes |
| 1986 | 362 | 99% | Yes |
| 1987 | 362 | 99% | Yes |
| 1988 | 354 | 97% | Yes |
| 1989 | 303 | 83% | No |
| 1990 | 354 | 97% | Yes |
| 1991 | 363 | 99% | Yes |
| 1992 | 364 | 99% | Yes |
| 1993 | 354 | 97% | Yes |
| 1994 | 354 | 97% | Yes |
| 1995 | 237 | 65% | No |
| 1996 | 352 | 96% | Yes |
| 1997 | 346 | 95% | Yes |
| 1998 | 350 | 96% | Yes |
| 1999 | 363 | 99% | Yes |
| 2000 | 361 | 99% | Yes |
| 2001 | 331 | 91% | Yes |
| 2002 | 31 | 8% | No |
| 2003 | 364 | 100% | Yes |
| 2004 | 363 | 99% | Yes |
| 2005 | 344 | 94% | Yes |
| 2006 | 351 | 96% | Yes |
| 2007 | 355 | 97% | Yes |
| 2008 | 365 | 100% | Yes |
| 2009 | 349 | 96% | Yes |
| 2010 | 351 | 96% | Yes |
| 2011 | 348 | 95% | Yes |
| 2012 | 357 | 98% | Yes |
| 2013 | 352 | 96% | Yes |
| 2014 | 354 | 97% | Yes |
| 2015 | 355 | 97% | Yes |
| 2016 | 365 | 100% | Yes |
| 2017 | 361 | 99% | Yes |
| 2018 | 353 | 97% | Yes |
| 2019 | 357 | 98% | Yes |
| 2020 | 347 | 95% | Yes |
| 2021 | 340 | 93% | Yes |
| 2022 | 332 | 91% | Yes |
| 2023 | 325 | 89% | No |
| 2024 | 301 | 82% | No |
| 2025 | 268 | 73% | No |
| 2026 | 193 | 53% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 3 August 2026 | Natl Arboretum Dc, US | daily rain | 40.4 mm (1.6 in) | 5.3 mm (0.21 in) | 57 years | 27 of 100 (Routine) |
| 5 July 2026 | Natl Arboretum Dc, US | daily high max | 39.4 C (102.9 F) | 1.6 C (2.9 F) | 27 years | 20 of 100 (Routine) |
| 4 July 2026 | Natl Arboretum Dc, US | daily high max | 39.4 C (102.9 F) | 2.2 C (4.0 F) | 71 years | 35 of 100 (Notable) |
| 4 July 2026 | Natl Arboretum Dc, US | daily high min | 27.8 C (82.0 F) | 2.2 C (4.0 F) | 27 years | 22 of 100 (Routine) |
| 3 July 2026 | Natl Arboretum Dc, US | daily high max | 39.4 C (102.9 F) | 1.1 C (2.0 F) | 60 years | 28 of 100 (Routine) |
| 3 July 2026 | Natl Arboretum Dc, US | daily high min | 26.7 C (80.1 F) | 1.7 C (3.1 F) | 8 years | 14 of 100 (Routine) |
| 2 July 2026 | Natl Arboretum Dc, US | daily high max | 37.2 C (99.0 F) | 0.5 C (0.9 F) | 60 years | 26 of 100 (Routine) |
| 24 May 2026 | Natl Arboretum Dc, US | daily low max | 13.3 C (55.9 F) | 0.6 C (1.1 F) | 23 years | 14 of 100 (Routine) |
| 23 May 2026 | Natl Arboretum Dc, US | daily low max (Tie) | 15.0 C (59.0 F) | tie | 0 years | 1 of 100 (Routine) |
| 20 May 2026 | Natl Arboretum Dc, US | daily high max | 35.6 C (96.1 F) | 1.2 C (2.2 F) | 29 years | 17 of 100 (Routine) |
| 22 April 2026 | Natl Arboretum Dc, US | daily low min | 0.0 C (32.0 F) | 0.6 C (1.1 F) | 4 years | 9 of 100 (Routine) |
| 21 April 2026 | Natl Arboretum Dc, US | daily low min | -0.6 C (30.9 F) | 1.2 C (2.2 F) | 69 years | 29 of 100 (Routine) |
| 18 April 2026 | Natl Arboretum Dc, US | daily high min (Tie) | 13.9 C (57.0 F) | tie | 52 years | 5 of 100 (Routine) |
| 17 April 2026 | Natl Arboretum Dc, US | daily high max | 33.3 C (91.9 F) | 1.1 C (2.0 F) | 49 years | 22 of 100 (Routine) |
| 16 April 2026 | Natl Arboretum Dc, US | daily high max | 32.8 C (91.0 F) | 2.8 C (5.0 F) | 65 years | 30 of 100 (Routine) |
| 16 April 2026 | Natl Arboretum Dc, US | daily high min (Tie) | 16.7 C (62.1 F) | tie | 59 years | 6 of 100 (Routine) |
| 15 April 2026 | Natl Arboretum Dc, US | daily high max (Tie) | 31.7 C (89.1 F) | tie | 65 years | 6 of 100 (Routine) |
| 5 April 2026 | Natl Arboretum Dc, US | monthly high min (Tie) | 21.1 C (70.0 F) | tie | 8 years | 4 of 100 (Routine) |
| 2 April 2026 | Natl Arboretum Dc, US | daily high min | 15.0 C (59.0 F) | 1.7 C (3.1 F) | 28 years | 18 of 100 (Routine) |
| 2 April 2026 | Natl Arboretum Dc, US | daily high max (Tie) | 31.1 C (88.0 F) | tie | 63 years | 6 of 100 (Routine) |
Climate Trend
66 complete years, 1949 to 2023| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1949 | 15.1 C | +1.23 C |
| 1950 | 13.7 C | -0.20 C |
| 1951 | 14.1 C | +0.21 C |
| 1954 | 14.6 C | +0.70 C |
| 1955 | 14.4 C | +0.53 C |
| 1956 | 14.2 C | +0.28 C |
| 1957 | 14.6 C | +0.71 C |
| 1958 | 12.9 C | -1.03 C |
| 1959 | 15.0 C | +1.07 C |
| 1960 | 13.4 C | -0.48 C |
| 1961 | 13.8 C | -0.12 C |
| 1962 | 13.4 C | -0.47 C |
| 1963 | 13.5 C | -0.45 C |
| 1964 | 14.1 C | +0.21 C |
| 1965 | 13.7 C | -0.17 C |
| 1966 | 13.4 C | -0.55 C |
| 1967 | 13.1 C | -0.81 C |
| 1968 | 13.9 C | -0.06 C |
| 1969 | 13.5 C | -0.46 C |
| 1970 | 13.8 C | -0.09 C |
| 1971 | 14.0 C | +0.04 C |
| 1972 | 13.4 C | -0.51 C |
| 1973 | 14.1 C | +0.16 C |
| 1974 | 13.6 C | -0.28 C |
| 1975 | 13.6 C | -0.28 C |
| 1976 | 12.9 C | -1.03 C |
| 1977 | 13.5 C | -0.41 C |
| 1978 | 12.7 C | -1.18 C |
| 1979 | 12.7 C | -1.24 C |
| 1981 | 12.8 C | -1.11 C |
| 1982 | 12.9 C | -0.98 C |
| 1983 | 13.1 C | -0.86 C |
| 1984 | 12.9 C | -1.00 C |
| 1985 | 13.2 C | -0.72 C |
| 1986 | 12.8 C | -1.09 C |
| 1987 | 13.2 C | -0.71 C |
| 1988 | 12.4 C | -1.49 C |
| 1990 | 14.7 C | +0.81 C |
| 1991 | 15.0 C | +1.09 C |
| 1992 | 13.0 C | -0.92 C |
| 1993 | 13.5 C | -0.44 C |
| 1994 | 13.4 C | -0.48 C |
| 1996 | 12.5 C | -1.40 C |
| 1997 | 12.9 C | -1.00 C |
| 1998 | 15.3 C | +1.37 C |
| 1999 | 14.4 C | +0.48 C |
| 2000 | 13.5 C | -0.40 C |
| 2003 | 13.3 C | -0.62 C |
| 2004 | 14.0 C | +0.09 C |
| 2006 | 14.8 C | +0.86 C |
| 2007 | 14.4 C | +0.44 C |
| 2008 | 14.0 C | +0.13 C |
| 2009 | 14.5 C | +0.63 C |
| 2010 | 14.6 C | +0.66 C |
| 2011 | 15.1 C | +1.21 C |
| 2012 | 15.6 C | +1.68 C |
| 2013 | 14.3 C | +0.36 C |
| 2014 | 13.7 C | -0.18 C |
| 2015 | 14.8 C | +0.90 C |
| 2016 | 15.2 C | +1.31 C |
| 2017 | 15.2 C | +1.31 C |
| 2018 | 14.9 C | +0.98 C |
| 2019 | 15.1 C | +1.17 C |
| 2020 | 15.3 C | +1.38 C |
| 2022 | 14.4 C | +0.51 C |
| 2023 | 14.9 C | +1.03 C |
The annual mean temperature here has risen by 0.13 C (0.04 to 0.22) per decade over 1949 to 2023. In Fahrenheit: 0.2 F (0.1 to 0.4) per decade. The slope is a straight line fitted to 66 complete years; the brackets give its 95 percent interval.
| Measure | Per decade (C) | Per decade (F) | Period | Complete years | Reading |
|---|---|---|---|---|---|
| Annual mean temperature | 0.13 C (0.04 to 0.22) per decade | 0.2 F (0.1 to 0.4) per decade | 1949 to 2023 | 66 | Rise |
| Mean daily maximum | 0.04 C (-0.05 to 0.14) per decade | 0.1 F (-0.1 to 0.2) per decade | 1949 to 2023 | 66 | Not clearly different from zero |
| Mean daily minimum | 0.2 C (0.1 to 0.3) per decade | 0.4 F (0.2 to 0.6) per decade | 1949 to 2023 | 66 | 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) | 41.1 C (106.0 F) | 2011 | 37.2 C (99.0 F) | 79 |
| Coldest night (TNn) | -23.3 C (-9.9 F) | 1982 | -13.3 C (8.1 F) | 79 |
| Wettest day (Rx1day) | 187.2 mm (7.4 in) | 2006 | 67.3 mm (2.6 in) | 79 |
| Wettest five days (Rx5day) | 254.0 mm (10.0 in) | 2006 | 98.0 mm (3.9 in) | 79 |
| Longest dry spell (CDD) | 43 days | 2000 | 19 days | 79 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1948 | 38.3 C (100.9 F) |
| 1949 | 37.2 C (99.0 F) |
| 1950 | 35.0 C (95.0 F) |
| 1951 | 36.1 C (97.0 F) |
| 1952 | 37.8 C (100.0 F) |
| 1953 | 38.9 C (102.0 F) |
| 1954 | 40.0 C (104.0 F) |
| 1955 | 38.3 C (100.9 F) |
| 1956 | 36.7 C (98.1 F) |
| 1957 | 38.9 C (102.0 F) |
| 1958 | 35.6 C (96.1 F) |
| 1959 | 37.8 C (100.0 F) |
| 1960 | 35.0 C (95.0 F) |
| 1961 | 35.6 C (96.1 F) |
| 1962 | 37.2 C (99.0 F) |
| 1963 | 36.7 C (98.1 F) |
| 1964 | 36.7 C (98.1 F) |
| 1965 | 35.6 C (96.1 F) |
| 1966 | 38.3 C (100.9 F) |
| 1967 | 34.4 C (93.9 F) |
| 1968 | 36.7 C (98.1 F) |
| 1969 | 37.2 C (99.0 F) |
| 1970 | 36.1 C (97.0 F) |
| 1971 | 33.9 C (93.0 F) |
| 1972 | 35.6 C (96.1 F) |
| 1973 | 36.1 C (97.0 F) |
| 1974 | 36.1 C (97.0 F) |
| 1975 | 36.1 C (97.0 F) |
| 1976 | 35.0 C (95.0 F) |
| 1977 | 38.3 C (100.9 F) |
| 1978 | 36.7 C (98.1 F) |
| 1979 | 34.4 C (93.9 F) |
| 1980 | 38.3 C (100.9 F) |
| 1981 | 36.7 C (98.1 F) |
| 1982 | 36.1 C (97.0 F) |
| 1983 | 39.4 C (102.9 F) |
| 1984 | 35.6 C (96.1 F) |
| 1985 | 37.2 C (99.0 F) |
| 1986 | 34.4 C (93.9 F) |
| 1987 | 37.2 C (99.0 F) |
| 1988 | 39.4 C (102.9 F) |
| 1989 | 36.7 C (98.1 F) |
| 1990 | 37.8 C (100.0 F) |
| 1991 | 38.9 C (102.0 F) |
| 1992 | 36.7 C (98.1 F) |
| 1993 | 38.3 C (100.9 F) |
| 1994 | 37.8 C (100.0 F) |
| 1995 | 38.3 C (100.9 F) |
| 1996 | 36.1 C (97.0 F) |
| 1997 | 40.0 C (104.0 F) |
| 1998 | 38.3 C (100.9 F) |
| 1999 | 40.0 C (104.0 F) |
| 2000 | 37.2 C (99.0 F) |
| 2001 | 38.9 C (102.0 F) |
| 2002 | 16.7 C (62.1 F) |
| 2003 | 34.4 C (93.9 F) |
| 2004 | 33.3 C (91.9 F) |
| 2005 | 36.7 C (98.1 F) |
| 2006 | 37.2 C (99.0 F) |
| 2007 | 38.3 C (100.9 F) |
| 2008 | 35.6 C (96.1 F) |
| 2009 | 37.8 C (100.0 F) |
| 2010 | 38.3 C (100.9 F) |
| 2011 | 41.1 C (106.0 F) |
| 2012 | 40.0 C (104.0 F) |
| 2013 | 36.1 C (97.0 F) |
| 2014 | 36.7 C (98.1 F) |
| 2015 | 36.1 C (97.0 F) |
| 2016 | 37.2 C (99.0 F) |
| 2017 | 36.7 C (98.1 F) |
| 2018 | 36.7 C (98.1 F) |
| 2019 | 37.8 C (100.0 F) |
| 2020 | 37.8 C (100.0 F) |
| 2021 | 37.2 C (99.0 F) |
| 2022 | 36.7 C (98.1 F) |
| 2023 | 36.7 C (98.1 F) |
| 2024 | 38.9 C (102.0 F) |
| 2025 | 38.3 C (100.9 F) |
| 2026 | 39.4 C (102.9 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1948 | -12.8 C (9.0 F) |
| 1949 | -10.0 C (14.0 F) |
| 1950 | -11.7 C (10.9 F) |
| 1951 | -13.9 C (7.0 F) |
| 1952 | -11.1 C (12.0 F) |
| 1953 | -7.2 C (19.0 F) |
| 1954 | -11.7 C (10.9 F) |
| 1955 | -13.9 C (7.0 F) |
| 1956 | -8.9 C (16.0 F) |
| 1957 | -16.7 C (1.9 F) |
| 1958 | -16.1 C (3.0 F) |
| 1959 | -13.9 C (7.0 F) |
| 1960 | -15.0 C (5.0 F) |
| 1961 | -18.3 C (-0.9 F) |
| 1962 | -14.4 C (6.1 F) |
| 1963 | -16.7 C (1.9 F) |
| 1964 | -15.0 C (5.0 F) |
| 1965 | -15.0 C (5.0 F) |
| 1966 | -13.3 C (8.1 F) |
| 1967 | -15.6 C (3.9 F) |
| 1968 | -16.1 C (3.0 F) |
| 1969 | -10.6 C (12.9 F) |
| 1970 | -14.4 C (6.1 F) |
| 1971 | -12.2 C (10.0 F) |
| 1972 | -16.7 C (1.9 F) |
| 1973 | -12.8 C (9.0 F) |
| 1974 | -11.7 C (10.9 F) |
| 1975 | -10.6 C (12.9 F) |
| 1976 | -14.4 C (6.1 F) |
| 1977 | -18.3 C (-0.9 F) |
| 1978 | -12.2 C (10.0 F) |
| 1979 | -16.7 C (1.9 F) |
| 1980 | -16.1 C (3.0 F) |
| 1981 | -15.0 C (5.0 F) |
| 1982 | -23.3 C (-9.9 F) |
| 1983 | -17.8 C (0.0 F) |
| 1984 | -20.0 C (-4.0 F) |
| 1985 | -21.1 C (-6.0 F) |
| 1986 | -13.3 C (8.1 F) |
| 1987 | -17.2 C (1.0 F) |
| 1988 | -16.7 C (1.9 F) |
| 1989 | -13.9 C (7.0 F) |
| 1990 | -10.0 C (14.0 F) |
| 1991 | -10.0 C (14.0 F) |
| 1992 | -10.6 C (12.9 F) |
| 1993 | -12.8 C (9.0 F) |
| 1994 | -20.6 C (-5.1 F) |
| 1995 | -14.4 C (6.1 F) |
| 1996 | -17.8 C (0.0 F) |
| 1997 | -14.4 C (6.1 F) |
| 1998 | -10.0 C (14.0 F) |
| 1999 | -13.9 C (7.0 F) |
| 2000 | -11.7 C (10.9 F) |
| 2001 | -9.4 C (15.1 F) |
| 2002 | -10.6 C (12.9 F) |
| 2003 | -12.8 C (9.0 F) |
| 2004 | -13.9 C (7.0 F) |
| 2005 | -12.8 C (9.0 F) |
| 2006 | -10.0 C (14.0 F) |
| 2007 | -12.2 C (10.0 F) |
| 2008 | -9.4 C (15.1 F) |
| 2009 | -13.9 C (7.0 F) |
| 2010 | -12.2 C (10.0 F) |
| 2011 | -12.2 C (10.0 F) |
| 2012 | -9.4 C (15.1 F) |
| 2013 | -9.4 C (15.1 F) |
| 2014 | -15.0 C (5.0 F) |
| 2015 | -15.6 C (3.9 F) |
| 2016 | -11.7 C (10.9 F) |
| 2017 | -9.4 C (15.1 F) |
| 2018 | -13.3 C (8.1 F) |
| 2019 | -13.3 C (8.1 F) |
| 2020 | -6.7 C (19.9 F) |
| 2021 | -5.0 C (23.0 F) |
| 2022 | -13.3 C (8.1 F) |
| 2023 | -8.9 C (16.0 F) |
| 2024 | -11.1 C (12.0 F) |
| 2025 | -7.8 C (18.0 F) |
| 2026 | -12.2 C (10.0 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1948 | 69.9 mm (2.8 in) |
| 1949 | 43.4 mm (1.7 in) |
| 1950 | 107.4 mm (4.2 in) |
| 1951 | 67.3 mm (2.6 in) |
| 1952 | 87.9 mm (3.5 in) |
| 1953 | 61.0 mm (2.4 in) |
| 1954 | 83.6 mm (3.3 in) |
| 1955 | 149.4 mm (5.9 in) |
| 1956 | 43.7 mm (1.7 in) |
| 1957 | 55.9 mm (2.2 in) |
| 1958 | 85.6 mm (3.4 in) |
| 1959 | 98.8 mm (3.9 in) |
| 1960 | 91.4 mm (3.6 in) |
| 1961 | 81.5 mm (3.2 in) |
| 1962 | 58.7 mm (2.3 in) |
| 1963 | 83.8 mm (3.3 in) |
| 1964 | 43.2 mm (1.7 in) |
| 1965 | 59.2 mm (2.3 in) |
| 1966 | 120.1 mm (4.7 in) |
| 1967 | 76.2 mm (3.0 in) |
| 1968 | 49.8 mm (2.0 in) |
| 1969 | 110.2 mm (4.3 in) |
| 1970 | 113.3 mm (4.5 in) |
| 1971 | 91.9 mm (3.6 in) |
| 1972 | 159.5 mm (6.3 in) |
| 1973 | 94.5 mm (3.7 in) |
| 1974 | 72.1 mm (2.8 in) |
| 1975 | 130.0 mm (5.1 in) |
| 1976 | 82.0 mm (3.2 in) |
| 1977 | 47.2 mm (1.9 in) |
| 1978 | 58.7 mm (2.3 in) |
| 1979 | 157.0 mm (6.2 in) |
| 1980 | 42.2 mm (1.7 in) |
| 1981 | 36.3 mm (1.4 in) |
| 1982 | 43.9 mm (1.7 in) |
| 1983 | 85.1 mm (3.4 in) |
| 1984 | 66.3 mm (2.6 in) |
| 1985 | 102.9 mm (4.1 in) |
| 1986 | 49.8 mm (2.0 in) |
| 1987 | 73.7 mm (2.9 in) |
| 1988 | 57.7 mm (2.3 in) |
| 1989 | 52.1 mm (2.1 in) |
| 1990 | 56.4 mm (2.2 in) |
| 1991 | 35.6 mm (1.4 in) |
| 1992 | 45.0 mm (1.8 in) |
| 1993 | 63.5 mm (2.5 in) |
| 1994 | 61.7 mm (2.4 in) |
| 1995 | 56.9 mm (2.2 in) |
| 1996 | 73.9 mm (2.9 in) |
| 1997 | 91.2 mm (3.6 in) |
| 1998 | 55.1 mm (2.2 in) |
| 1999 | 69.1 mm (2.7 in) |
| 2000 | 54.6 mm (2.1 in) |
| 2001 | 40.9 mm (1.6 in) |
| 2002 | 34.8 mm (1.4 in) |
| 2003 | 70.1 mm (2.8 in) |
| 2004 | 63.5 mm (2.5 in) |
| 2005 | 126.5 mm (5.0 in) |
| 2006 | 187.2 mm (7.4 in) |
| 2007 | 101.1 mm (4.0 in) |
| 2008 | 92.7 mm (3.6 in) |
| 2009 | 64.8 mm (2.6 in) |
| 2010 | 73.9 mm (2.9 in) |
| 2011 | 112.5 mm (4.4 in) |
| 2012 | 77.2 mm (3.0 in) |
| 2013 | 60.2 mm (2.4 in) |
| 2014 | 59.2 mm (2.3 in) |
| 2015 | 72.4 mm (2.9 in) |
| 2016 | 46.2 mm (1.8 in) |
| 2017 | 121.9 mm (4.8 in) |
| 2018 | 102.1 mm (4.0 in) |
| 2019 | 48.3 mm (1.9 in) |
| 2020 | 73.2 mm (2.9 in) |
| 2021 | 53.1 mm (2.1 in) |
| 2022 | 50.5 mm (2.0 in) |
| 2023 | 64.8 mm (2.6 in) |
| 2024 | 57.7 mm (2.3 in) |
| 2025 | 41.1 mm (1.6 in) |
| 2026 | 40.4 mm (1.6 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1948 | 123.7 mm (4.9 in) |
| 1949 | 63.5 mm (2.5 in) |
| 1950 | 152.8 mm (6.0 in) |
| 1951 | 104.1 mm (4.1 in) |
| 1952 | 133.9 mm (5.3 in) |
| 1953 | 78.2 mm (3.1 in) |
| 1954 | 87.4 mm (3.4 in) |
| 1955 | 198.5 mm (7.8 in) |
| 1956 | 76.9 mm (3.0 in) |
| 1957 | 78.6 mm (3.1 in) |
| 1958 | 130.6 mm (5.1 in) |
| 1959 | 100.4 mm (4.0 in) |
| 1960 | 124.4 mm (4.9 in) |
| 1961 | 145.5 mm (5.7 in) |
| 1962 | 89.9 mm (3.5 in) |
| 1963 | 166.9 mm (6.6 in) |
| 1964 | 73.4 mm (2.9 in) |
| 1965 | 59.2 mm (2.3 in) |
| 1966 | 128.5 mm (5.1 in) |
| 1967 | 118.5 mm (4.7 in) |
| 1968 | 84.8 mm (3.3 in) |
| 1969 | 150.6 mm (5.9 in) |
| 1970 | 113.3 mm (4.5 in) |
| 1971 | 98.0 mm (3.9 in) |
| 1972 | 236.4 mm (9.3 in) |
| 1973 | 111.1 mm (4.4 in) |
| 1974 | 94.5 mm (3.7 in) |
| 1975 | 245.5 mm (9.7 in) |
| 1976 | 137.4 mm (5.4 in) |
| 1977 | 91.4 mm (3.6 in) |
| 1978 | 91.2 mm (3.6 in) |
| 1979 | 160.3 mm (6.3 in) |
| 1980 | 73.7 mm (2.9 in) |
| 1981 | 62.9 mm (2.5 in) |
| 1982 | 90.1 mm (3.5 in) |
| 1983 | 87.4 mm (3.4 in) |
| 1984 | 103.1 mm (4.1 in) |
| 1985 | 109.8 mm (4.3 in) |
| 1986 | 68.4 mm (2.7 in) |
| 1987 | 111.3 mm (4.4 in) |
| 1988 | 69.6 mm (2.7 in) |
| 1989 | 91.7 mm (3.6 in) |
| 1990 | 125.0 mm (4.9 in) |
| 1991 | 66.8 mm (2.6 in) |
| 1992 | 61.0 mm (2.4 in) |
| 1993 | 82.8 mm (3.3 in) |
| 1994 | 105.4 mm (4.1 in) |
| 1995 | 68.4 mm (2.7 in) |
| 1996 | 93.0 mm (3.7 in) |
| 1997 | 98.0 mm (3.9 in) |
| 1998 | 86.9 mm (3.4 in) |
| 1999 | 123.7 mm (4.9 in) |
| 2000 | 82.1 mm (3.2 in) |
| 2001 | 83.6 mm (3.3 in) |
| 2002 | 57.9 mm (2.3 in) |
| 2003 | 118.8 mm (4.7 in) |
| 2004 | 89.0 mm (3.5 in) |
| 2005 | 198.9 mm (7.8 in) |
| 2006 | 254.0 mm (10.0 in) |
| 2007 | 161.1 mm (6.3 in) |
| 2008 | 190.5 mm (7.5 in) |
| 2009 | 90.9 mm (3.6 in) |
| 2010 | 135.4 mm (5.3 in) |
| 2011 | 163.0 mm (6.4 in) |
| 2012 | 88.8 mm (3.5 in) |
| 2013 | 157.2 mm (6.2 in) |
| 2014 | 102.1 mm (4.0 in) |
| 2015 | 116.3 mm (4.6 in) |
| 2016 | 73.9 mm (2.9 in) |
| 2017 | 123.4 mm (4.9 in) |
| 2018 | 171.2 mm (6.7 in) |
| 2019 | 84.8 mm (3.3 in) |
| 2020 | 106.2 mm (4.2 in) |
| 2021 | 101.6 mm (4.0 in) |
| 2022 | 92.4 mm (3.6 in) |
| 2023 | 70.8 mm (2.8 in) |
| 2024 | 66.9 mm (2.6 in) |
| 2025 | 79.6 mm (3.1 in) |
| 2026 | 63.7 mm (2.5 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1948 | 10 days |
| 1949 | 18 days |
| 1950 | 16 days |
| 1951 | 15 days |
| 1952 | 22 days |
| 1953 | 18 days |
| 1954 | 18 days |
| 1955 | 22 days |
| 1956 | 16 days |
| 1957 | 25 days |
| 1958 | 16 days |
| 1959 | 13 days |
| 1960 | 14 days |
| 1961 | 16 days |
| 1962 | 23 days |
| 1963 | 32 days |
| 1964 | 29 days |
| 1965 | 20 days |
| 1966 | 29 days |
| 1967 | 23 days |
| 1968 | 21 days |
| 1969 | 19 days |
| 1970 | 17 days |
| 1971 | 15 days |
| 1972 | 12 days |
| 1973 | 25 days |
| 1974 | 19 days |
| 1975 | 17 days |
| 1976 | 16 days |
| 1977 | 30 days |
| 1978 | 14 days |
| 1979 | 12 days |
| 1980 | 18 days |
| 1981 | 18 days |
| 1982 | 16 days |
| 1983 | 14 days |
| 1984 | 21 days |
| 1985 | 33 days |
| 1986 | 21 days |
| 1987 | 20 days |
| 1988 | 23 days |
| 1989 | 21 days |
| 1990 | 19 days |
| 1991 | 22 days |
| 1992 | 17 days |
| 1993 | 22 days |
| 1994 | 15 days |
| 1995 | 12 days |
| 1996 | 12 days |
| 1997 | 15 days |
| 1998 | 25 days |
| 1999 | 20 days |
| 2000 | 43 days |
| 2001 | 33 days |
| 2002 | 5 days |
| 2003 | 15 days |
| 2004 | 17 days |
| 2005 | 29 days |
| 2006 | 32 days |
| 2007 | 24 days |
| 2008 | 23 days |
| 2009 | 20 days |
| 2010 | 19 days |
| 2011 | 15 days |
| 2012 | 16 days |
| 2013 | 15 days |
| 2014 | 12 days |
| 2015 | 14 days |
| 2016 | 19 days |
| 2017 | 23 days |
| 2018 | 19 days |
| 2019 | 37 days |
| 2020 | 10 days |
| 2021 | 19 days |
| 2022 | 11 days |
| 2023 | 11 days |
| 2024 | 22 days |
| 2025 | 15 days |
| 2026 | 20 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
66 years with a frostAcross 66 years with a frost, the median last spring frost at Natl Arboretum Dc falls on 9 April and the median first autumn frost on 2 November, which leaves a median of 208 days between them.
In 1988 to 2023 the median growing season was 220 days. That is 19 days more than in 1949 to 1981.
Fitted over all years, the growing season changes by +3.3 days per decade at this station.
| Measure | Median, all years | Earliest period (1949 to 1981) | Recent period (1988 to 2023) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 9 April | 11 April | 31 March | 11 days earlier | -1.9 days per decade |
| First autumn frost | 2 November | 31 October | 7 November | 7 days later | +1.4 days per decade |
| Growing days | 208 days | 201 days | 220 days | 19 days more | +3.3 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.
Rainfall Return Levels
71 years, 1949 to 2023A day with at least 70.1 mm (2.8 in) of rain is expected about once in 2 years. A day with at least 195.3 mm (7.7 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 70.1 mm (2.8 in) | |
| 5 years | 97.8 mm (3.9 in) | |
| 10 years | 118.3 mm (4.7 in) | |
| 25 years | 146.9 mm (5.8 in) | |
| 50 years | 170.2 mm (6.7 in) | |
| 100 years | 195.3 mm (7.7 in) | Longer than the 71 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, 71 years of values from 1949 to 2023.
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: 187.2 mm (7.4 in) in 2006; 159.5 mm (6.3 in) in 1972; 157.0 mm (6.2 in) in 1979.
Station Changes
1 suspectedOne change was suspected in the annual mean temperature of Natl Arboretum Dc, at 2009. Each is measured against neighbouring stations.
- Relative to 5 neighbouring stations, the station's annual mean temperature from 2009 ran 0.3 C (0.6 F) higher than in the years before (possible change).
| Year | Shift (C) | Shift (F) | Strength | Neighbours |
|---|---|---|---|---|
| 2009 | +0.3 | +0.6 | possible | 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
2008 to 2023 against 1961 to 1990Over 2008 to 2023, Natl Arboretum Dc had a mean temperature of 14.8 C (58.6 F) and 1,150.4 mm (45.3 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Lead Hill (United States, 1,429 km away), Caruthersville (United States, 1,158 km away) and Evening Shade 1 NNE (United States, 1,328 km away).
| Twin station | Country | Distance away | Mean temperature, 1961-1990 | Rain a year, 1961-1990 | Climate difference |
|---|---|---|---|---|---|
| Lead Hill | United States | 1,429 km (888 mi) | 14.8 C (58.6 F) | 1,100.3 mm (43.3 in) | 0.73 |
| Caruthersville | United States | 1,158 km (720 mi) | 14.8 C (58.7 F) | 1,228.3 mm (48.4 in) | 0.76 |
| Evening Shade 1 NNE | United States | 1,328 km (825 mi) | 14.7 C (58.5 F) | 1,173.3 mm (46.2 in) | 0.77 |
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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2026-10-12).