May is one of the warmer months of the year in Washington, with average highs near 12.1°C and lows around 7.7°C (mean 9.9°C). It is one of the drier months, averaging 49 mm of rainfall and 84% relative humidity across the period.
May is one of the warmer months of the year in Washington. Across 45 years of records, the warmest May in Washington was 2024 — when the month averaged 11.9°C — while the coldest was 1996 at 7.7°C. Typical May days reach 12.1°C with nights near 7.7°C. The long-term trend is warming, about 0.4°C per decade.
May is one of the drier months in Washington, averaging 49 mm of rainfall. The wettest May on record was 1985 with 98 mm, while the driest were 1989 and 2020 at 17 mm.
Relative humidity in Washington during May averages 84%. The most humid May was 2024 at 91%, and the least humid was 2020 at 80%.
May receives about 4.6 kWh/m²/day of solar energy in Washington. The sunniest May was 2020 at 5.5 kWh/m²/day, and the cloudiest were 1985 and 1987 at 3.9.
Average wind speed in Washington during May is 4 m/s. The windiest May was 1986 at 5.4 m/s, while the calmest was 1990 at 2.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.1°C | 9.6°C | 10.2°C | 10.0°C | 10.8°C | +1.7°C |
| Avg High | 11.2°C | 11.7°C | 12.4°C | 12.2°C | 13.1°C | +1.9°C |
| Avg Low | 6.9°C | 7.4°C | 8.0°C | 7.8°C | 8.6°C | +1.7°C |
| Avg Rain | 55 mm | 44 mm | 48 mm | 53 mm | 47 mm | -8 mm |
May temperatures in Washington have risen by about 2°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 2.3°C (1997) to a record high of 20.9°C (2010).
Rainfall in May is one of the drier months, averaging 49 mm, with a wettest year of 98 mm.
A good time to visit Washington
May is a good time to visit Washington, with days averaging 12.1°C and nights around 7.7°C (mean 9.9°C, close to Washington's yearly average) and moderate rainfall. August and July are marginally more temperate, but May still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 13.6°C | 11.2°C | 8.8°C | 18.7°C | 5.3°C | 26 mm | 81% | 4.2 m/s | 5.3 |
| 2024 🔥 | 13.8°C | 11.9°C | 9.9°C | 17.1°C | 7.2°C | 72 mm | 91% | 3.3 m/s | 4.1 |
| 2023 | 13.4°C | 11.1°C | 8.8°C | 17.3°C | 5.9°C | 28 mm | 85% | 3 m/s | 4.9 |
| 2022 | 13.3°C | 11.1°C | 8.9°C | 15.4°C | 6.9°C | 55 mm | 84% | 4 m/s | 4.5 |
| 2021 | 11.1°C | 9.0°C | 6.8°C | 15.3°C | 2.7°C | 82 mm | 84% | 3.7 m/s | 4.5 |
| 2020 | 13.3°C | 10.7°C | 8.2°C | 17.9°C | 3.5°C | 17 mm | 80% | 3.9 m/s | 5.5 |
| 2019 | 12.2°C | 10.0°C | 7.8°C | 16.2°C | 4.5°C | 42 mm | 81% | 3.6 m/s | 4.7 |
| 2018 | 13.5°C | 10.9°C | 8.4°C | 17.3°C | 3.2°C | 33 mm | 86% | 3.5 m/s | 5.2 |
| 2017 | 13.2°C | 10.9°C | 8.6°C | 18.1°C | 6.1°C | 38 mm | 86% | 3.9 m/s | 4.7 |
| 2016 | 12.0°C | 10.0°C | 8.0°C | 14.4°C | 4.9°C | 34 mm | 86% | 4 m/s | 4.6 |
| 2015 | 11.4°C | 9.1°C | 6.9°C | 14.5°C | 3.0°C | 92 mm | 81% | 4.8 m/s | 4.6 |
| 2014 | 13.0°C | 11.0°C | 9.0°C | 16.7°C | 4.4°C | 78 mm | 84% | 3.7 m/s | 4.3 |
| 2013 | 11.3°C | 9.0°C | 6.7°C | 15.0°C | 3.9°C | 68 mm | 85% | 4.6 m/s | 4.6 |
| 2012 | 11.2°C | 9.1°C | 7.0°C | 18.1°C | 3.6°C | 67 mm | 85% | 3.9 m/s | 4.7 |
| 2011 | 12.8°C | 10.5°C | 8.3°C | 15.0°C | 4.4°C | 50 mm | 81% | 5.2 m/s | 4.8 |
| 2010 | 11.4°C | 9.2°C | 7.0°C | 20.9°C | 3.5°C | 25 mm | 81% | 3.5 m/s | 4.9 |
| 2009 | 12.6°C | 10.3°C | 8.0°C | 16.7°C | 5.9°C | 41 mm | 84% | 4.7 m/s | 5 |
| 2008 | 12.6°C | 10.6°C | 8.7°C | 16.4°C | 5.6°C | 27 mm | 85% | 3.9 m/s | 4.7 |
| 2007 | 12.3°C | 10.1°C | 8.0°C | 15.2°C | 6.5°C | 58 mm | 83% | 4.4 m/s | 4.4 |
| 2006 | 12.1°C | 9.8°C | 7.5°C | 15.8°C | 5.0°C | 79 mm | 84% | 4.3 m/s | 4.5 |
| 2005 | 11.8°C | 9.6°C | 7.3°C | 15.6°C | 4.1°C | 42 mm | 83% | 4.3 m/s | 4.8 |
| 2004 | 12.7°C | 10.4°C | 8.1°C | 16.8°C | 5.9°C | 33 mm | 83% | 3.4 m/s | 4.9 |
| 2003 | 12.8°C | 10.6°C | 8.3°C | 17.9°C | 5.7°C | 68 mm | 85% | 4.3 m/s | 4.6 |
| 2002 | 12.4°C | 10.3°C | 8.2°C | 17.8°C | 4.7°C | 56 mm | 86% | 4.6 m/s | 4.3 |
| 2001 | 12.9°C | 10.6°C | 8.2°C | 17.9°C | 4.8°C | 18 mm | 84% | 3.3 m/s | 5.2 |
| 2000 | 12.1°C | 9.8°C | 7.6°C | 17.7°C | 5.2°C | 58 mm | 86% | 3.7 m/s | 4.6 |
| 1999 | 12.6°C | 10.4°C | 8.3°C | 16.1°C | 6.2°C | 50 mm | 86% | 4 m/s | 4.4 |
| 1998 | 12.5°C | 10.5°C | 8.5°C | 17.5°C | 5.6°C | 61 mm | 87% | 3.9 m/s | 5.1 |
| 1997 | 11.9°C | 9.5°C | 7.1°C | 18.5°C | 2.3°C | 57 mm | 84% | 3.8 m/s | 4.4 |
| 1996 ❄️ | 9.7°C | 7.7°C | 5.7°C | 14.7°C | 3.0°C | 49 mm | 82% | 4.6 m/s | 4.5 |
| 1995 | 11.9°C | 9.5°C | 7.2°C | 17.1°C | 3.9°C | 39 mm | 81% | 3.8 m/s | 4.6 |
| 1994 | 10.3°C | 8.5°C | 6.8°C | 12.9°C | 5.3°C | 29 mm | 82% | 4.7 m/s | 4.8 |
| 1993 | 11.1°C | 9.1°C | 7.1°C | 15.0°C | 4.0°C | 82 mm | 86% | 4.3 m/s | 4 |
| 1992 | 12.8°C | 10.4°C | 8.0°C | 16.6°C | 4.3°C | 18 mm | 85% | 4.4 m/s | 5.3 |
| 1991 | 11.3°C | 9.4°C | 7.4°C | 16.0°C | 4.9°C | 21 mm | 84% | 3.9 m/s | 4 |
| 1990 | 13.0°C | 10.5°C | 8.1°C | 18.6°C | 5.4°C | 37 mm | 81% | 2.8 m/s | 4.8 |
| 1989 | 12.7°C | 10.2°C | 7.7°C | 15.4°C | 4.3°C | 17 mm | 83% | 3.7 m/s | 5.1 |
| 1988 | 11.5°C | 9.5°C | 7.5°C | 14.1°C | 5.3°C | 47 mm | 87% | 3.7 m/s | 4.2 |
| 1987 | 10.1°C | 8.0°C | 6.0°C | 15.9°C | 3.0°C | 45 mm | 85% | 4.3 m/s | 3.9 |
| 1986 | 11.3°C | 9.2°C | 7.1°C | 13.6°C | 4.8°C | 83 mm | 85% | 5.4 m/s | 4 |
| 1985 🌧️ | 10.6°C | 8.6°C | 6.5°C | 16.2°C | 3.1°C | 98 mm | 87% | 4 m/s | 3.9 |
| 1984 | 10.7°C | 8.6°C | 6.4°C | 14.0°C | 4.2°C | 29 mm | 83% | 3.8 m/s | 4.5 |
| 1983 | 10.0°C | 8.2°C | 6.3°C | 12.7°C | 4.1°C | 89 mm | 88% | 4 m/s | — |
| 1982 | 12.0°C | 9.5°C | 6.9°C | 16.6°C | 2.5°C | 22 mm | 82% | 4.1 m/s | — |
| 1981 | 11.9°C | 9.8°C | 7.7°C | 15.2°C | 3.0°C | 66 mm | 87% | 4 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 12.1°C with lows near 7.7°C (mean 9.9°C), based on 45 years of NASA POWER data.
May averages 49 mm of rainfall in Washington, one of the drier months. The wettest on record was 98 mm in 1985.
The hottest May reached 20.9°C in 2010. The coldest dipped to 2.3°C in 1997.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 2°C. Daytime highs moved from 11°C to 13°C and overnight lows from 6.8°C to 8.6°C over the same span.
May is one of the warmer months of the year in Washington and one of the drier months, so plan for around 12.1°C daytime highs and 7.7°C at night.
Not quite — May is the 7th coolest month in Washington, averaging 9.9°C.
For May in Washington, pack warm layers and a jacket for chilly mornings, with typical highs of 12.1°C and lows of 7.7°C.
Relative humidity in May averages 84% — quite humid.
Average wind speed in May is 4 m/s. The windiest May on record averaged 5.4 m/s (1986).
The wettest May on record was 1985 with 98 mm. On average, May sees 49 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Washington behaves each May, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for May specifically, along with year-by-year records and how the month has changed over the decades.
