August is one of the warmer months of the year in Washington, with average highs near 17.2°C and lows around 12.8°C (mean 15°C). It is about average for rainfall, averaging 70 mm of rainfall and 85% relative humidity across the period.
August is one of the warmer months of the year in Washington. Across 45 years of records, the warmest August in Washington was 1997 — when the month averaged 16.7°C — while the coldest was 1986 at 12.4°C. Typical August days reach 17.2°C with nights near 12.8°C. The long-term trend is warming, about 0.2°C per decade.
August is about average for rainfall in Washington, averaging 70 mm of rainfall. The wettest August on record was 2008 with 141 mm, while the driest was 1995 at 14 mm.
Relative humidity in Washington during August averages 85%. The most humid August was 2002 at 88%, and the least humid was 1989 at 82%.
August receives about 3.8 kWh/m²/day of solar energy in Washington. The sunniest August was 1995 at 4.6 kWh/m²/day, and the cloudiest was 1986 at 2.9.
Average wind speed in Washington during August is 4 m/s. The windiest August was 1985 at 5.3 m/s, while the calmest was 1983 at 2.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.3°C | 15.0°C | 15.3°C | 14.9°C | 15.6°C | +1.3°C |
| Avg High | 16.6°C | 17.3°C | 17.5°C | 17.1°C | 17.8°C | +1.2°C |
| Avg Low | 12.1°C | 12.7°C | 13.1°C | 12.6°C | 13.4°C | +1.3°C |
| Avg Rain | 67 mm | 55 mm | 84 mm | 86 mm | 53 mm | -14 mm |
August temperatures in Washington have risen by about 1°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 7.9°C (1986) to a record high of 24.2°C (1990).
Rainfall in August is about average for rainfall, averaging 70 mm, with a wettest year of 141 mm.
One of the best times to visit Washington
August is one of the best times to visit Washington. Expect days averaging 17.2°C and nights around 12.8°C (mean 15°C) — warmer than Washington's yearly average — with moderate rainfall (70 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 18.4°C | 16.0°C | 13.7°C | 22.0°C | 11.8°C | 27 mm | 82% | 4.1 m/s | 4.1 |
| 2024 | 17.7°C | 15.3°C | 13.0°C | 21.5°C | 10.6°C | 45 mm | 84% | 4.6 m/s | 3.9 |
| 2023 | 17.3°C | 15.2°C | 13.1°C | 20.2°C | 10.9°C | 69 mm | 85% | 3.8 m/s | 3.9 |
| 2022 | 18.9°C | 16.5°C | 14.2°C | 23.2°C | 11.1°C | 31 mm | 83% | 3.2 m/s | 4.5 |
| 2021 | 17.3°C | 15.3°C | 13.2°C | 19.2°C | 11.4°C | 47 mm | 85% | 3.6 m/s | 3.6 |
| 2020 | 17.1°C | 15.2°C | 13.3°C | 21.5°C | 9.9°C | 100 mm | 87% | 4.1 m/s | 3.4 |
| 2019 | 18.3°C | 16.0°C | 13.7°C | 21.3°C | 11.5°C | 100 mm | 85% | 4.5 m/s | 3.9 |
| 2018 | 17.6°C | 15.3°C | 13.0°C | 21.2°C | 10.0°C | 83 mm | 85% | 3.6 m/s | 3.7 |
| 2017 | 16.7°C | 14.5°C | 12.3°C | 19.0°C | 10.3°C | 63 mm | 85% | 4.1 m/s | 3.9 |
| 2016 | 17.3°C | 15.1°C | 12.9°C | 19.8°C | 9.7°C | 98 mm | 85% | 4.2 m/s | 4.1 |
| 2015 | 17.1°C | 14.8°C | 12.4°C | 19.7°C | 10.5°C | 78 mm | 84% | 4.1 m/s | 4 |
| 2014 | 16.2°C | 14.1°C | 12.0°C | 19.2°C | 8.9°C | 106 mm | 82% | 4.9 m/s | 4 |
| 2013 | 17.9°C | 15.5°C | 13.1°C | 20.9°C | 10.3°C | 66 mm | 85% | 3.8 m/s | 4.1 |
| 2012 | 17.0°C | 15.0°C | 12.9°C | 19.3°C | 8.9°C | 87 mm | 86% | 3.7 m/s | 3.8 |
| 2011 | 16.3°C | 14.2°C | 12.1°C | 19.0°C | 9.8°C | 100 mm | 85% | 3.9 m/s | 3.5 |
| 2010 | 16.5°C | 14.2°C | 12.0°C | 20.5°C | 9.3°C | 75 mm | 85% | 4.2 m/s | 3.8 |
| 2009 | 17.7°C | 15.4°C | 13.1°C | 20.3°C | 11.1°C | 76 mm | 85% | 4.4 m/s | 3.8 |
| 2008 🌧️ | 17.3°C | 15.3°C | 13.3°C | 19.3°C | 11.1°C | 141 mm | 87% | 4 m/s | 3.3 |
| 2007 | 16.7°C | 14.4°C | 12.1°C | 19.8°C | 10.5°C | 49 mm | 85% | 4.3 m/s | 4 |
| 2006 | 17.2°C | 15.1°C | 13.0°C | 21.5°C | 11.1°C | 105 mm | 85% | 4.2 m/s | 3.5 |
| 2005 | 17.2°C | 14.8°C | 12.3°C | 21.0°C | 10.4°C | 56 mm | 84% | 4.2 m/s | 4 |
| 2004 | 17.8°C | 15.8°C | 13.7°C | 21.6°C | 10.7°C | 140 mm | 87% | 3.9 m/s | 3.5 |
| 2003 | 18.0°C | 15.9°C | 13.7°C | 22.5°C | 10.4°C | 47 mm | 84% | 3.6 m/s | 4.1 |
| 2002 | 18.1°C | 15.9°C | 13.8°C | 21.5°C | 11.4°C | 73 mm | 88% | 3.4 m/s | 3.6 |
| 2001 | 17.7°C | 15.4°C | 13.1°C | 21.1°C | 11.1°C | 81 mm | 85% | 3.4 m/s | 3.8 |
| 2000 | 17.4°C | 15.2°C | 13.0°C | 19.9°C | 11.0°C | 67 mm | 85% | 3.4 m/s | 4 |
| 1999 | 16.5°C | 14.5°C | 12.5°C | 20.9°C | 9.7°C | 83 mm | 84% | 4 m/s | 3.8 |
| 1998 | 16.4°C | 14.2°C | 11.9°C | 20.7°C | 9.3°C | 42 mm | 85% | 4.6 m/s | 3.8 |
| 1997 🔥 | 19.0°C | 16.7°C | 14.4°C | 23.0°C | 10.8°C | 51 mm | 87% | 3.1 m/s | 3.9 |
| 1996 | 17.2°C | 15.0°C | 12.9°C | 21.0°C | 10.8°C | 55 mm | 85% | 3.6 m/s | 3.9 |
| 1995 | 18.8°C | 16.4°C | 14.0°C | 23.5°C | 11.4°C | 14 mm | 83% | 3.5 m/s | 4.6 |
| 1994 | 16.4°C | 14.3°C | 12.2°C | 20.9°C | 9.5°C | 64 mm | 84% | 4.1 m/s | 3.9 |
| 1993 | 15.5°C | 13.1°C | 10.8°C | 18.2°C | 8.7°C | 65 mm | 84% | 3.9 m/s | 3.8 |
| 1992 | 16.2°C | 13.9°C | 11.6°C | 18.4°C | 8.6°C | 97 mm | 83% | 4.9 m/s | 3.7 |
| 1991 | 18.2°C | 15.7°C | 13.2°C | 20.5°C | 11.1°C | 39 mm | 84% | 3.6 m/s | 4 |
| 1990 | 18.6°C | 16.0°C | 13.4°C | 24.2°C | 10.1°C | 44 mm | 82% | 4.2 m/s | 4 |
| 1989 | 17.3°C | 14.9°C | 12.5°C | 19.7°C | 10.2°C | 76 mm | 82% | 4.8 m/s | 4.1 |
| 1988 | 16.4°C | 14.0°C | 11.6°C | 19.0°C | 10.2°C | 54 mm | 84% | 4.4 m/s | 3.9 |
| 1987 | 15.8°C | 13.8°C | 11.9°C | 20.3°C | 9.3°C | 101 mm | 86% | 4.2 m/s | 3.2 |
| 1986 ❄️ | 14.4°C | 12.4°C | 10.5°C | 17.1°C | 7.9°C | 126 mm | 83% | 4.5 m/s | 2.9 |
| 1985 | 15.3°C | 13.1°C | 11.0°C | 17.7°C | 9.2°C | 79 mm | 85% | 5.3 m/s | 3.5 |
| 1984 | 18.1°C | 15.8°C | 13.5°C | 21.8°C | 10.6°C | 40 mm | 85% | 3.4 m/s | 4 |
| 1983 | 17.8°C | 15.5°C | 13.2°C | 21.2°C | 10.3°C | 30 mm | 84% | 2.9 m/s | — |
| 1982 | 16.7°C | 14.4°C | 12.1°C | 19.9°C | 8.7°C | 62 mm | 84% | 4.7 m/s | — |
| 1981 | 17.2°C | 14.9°C | 12.6°C | 20.2°C | 10.4°C | 32 mm | 85% | 3.3 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 17.2°C with lows near 12.8°C (mean 15°C), based on 45 years of NASA POWER data.
August averages 70 mm of rainfall in Washington, about average for rainfall. The wettest on record was 141 mm in 2008.
The hottest August reached 24.2°C in 1990. The coldest dipped to 7.9°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 1°C. Daytime highs moved from 17°C to 17.9°C and overnight lows from 12.5°C to 13.4°C over the same span.
August is one of the warmer months of the year in Washington and about average for rainfall, so plan for around 17.2°C daytime highs and 12.8°C at night.
Not quite — August is the 12th coolest month in Washington, averaging 15°C.
For August in Washington, pack light layers you can adjust through the day, with typical highs of 17.2°C and lows of 12.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 85% — quite humid.
Average wind speed in August is 4 m/s. The windiest August on record averaged 5.3 m/s (1985).
The wettest August on record was 2008 with 141 mm. On average, August sees 70 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 August, 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 August specifically, along with year-by-year records and how the month has changed over the decades.
