December is one of the cooler months of the year in Washington, with average highs near 6.7°C and lows around -1.4°C (mean 2.7°C). It is about average for rainfall, averaging 89 mm of rainfall and 83% relative humidity across the period.
December is one of the cooler months of the year in Washington. Across 45 years of records, the warmest December in Washington was 2015 — when the month averaged 9.2°C — while the coldest was 1989 at -4.7°C. Typical December days reach 6.7°C with nights near -1.4°C. The long-term trend is warming, about 0.5°C per decade.
December is about average for rainfall in Washington, averaging 89 mm of rainfall. The wettest December on record was 2023 with 180 mm, while the driest was 2021 at 19 mm.
Relative humidity in Washington during December averages 83%. The most humid December was 1996 at 90%, and the least humid was 1998 at 71%.
December receives about 1.9 kWh/m²/day of solar energy in Washington. The sunniest Decembers were 1995, 2001 and 2003 at 2.2 kWh/m²/day, and the cloudiest was 1984 at 1.5.
Average wind speed in Washington during December is 2.8 m/s. The windiest December was 2010 at 3.7 m/s, while the calmest were 2015, 2021 and 2023 at 2.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 1.3°C | 2.8°C | 2.2°C | 3.7°C | 3.5°C | +2.2°C |
| Avg High | 5.4°C | 6.9°C | 6.2°C | 7.6°C | 7.9°C | +2.5°C |
| Avg Low | -2.8°C | -1.3°C | -1.9°C | -0.2°C | -0.9°C | +1.9°C |
| Avg Rain | 76 mm | 91 mm | 93 mm | 91 mm | 93 mm | +17 mm |
December temperatures in Washington have risen by about 1.7°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -18.9°C (1983) to a record high of 23.8°C (1998).
Rainfall in December is about average for rainfall, averaging 89 mm, with a wettest year of 180 mm.
A quieter season to visit Washington
If your dates are flexible, the more temperate months of June and September tend to be the most comfortable for visiting Washington. That said, December — with days averaging 6.7°C and nights around -1.4°C (mean 2.7°C) and higher rainfall (89 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 5.1°C | 1.0°C | -3.1°C | 13.3°C | -9.2°C | 42 mm | 76% | 3 m/s | — |
| 2024 | 7.7°C | 3.4°C | -0.9°C | 17.7°C | -5.8°C | 73 mm | 78% | 2.7 m/s | 2 |
| 2023 🌧️ | 9.9°C | 5.5°C | 1.0°C | 15.8°C | -3.7°C | 180 mm | 86% | 2.4 m/s | 1.8 |
| 2022 | 6.8°C | 2.2°C | -2.3°C | 16.6°C | -13.4°C | 115 mm | 83% | 2.6 m/s | 2.1 |
| 2021 | 11.1°C | 6.4°C | 1.8°C | 18.6°C | -4.6°C | 19 mm | 79% | 2.4 m/s | 2 |
| 2020 | 6.5°C | 2.3°C | -1.9°C | 16.4°C | -10.5°C | 127 mm | 86% | 2.9 m/s | 2 |
| 2019 | 7.5°C | 3.6°C | -0.3°C | 17.6°C | -7.5°C | 89 mm | 85% | 2.5 m/s | 1.9 |
| 2018 | 7.4°C | 3.6°C | -0.1°C | 16.6°C | -5.4°C | 146 mm | 87% | 2.5 m/s | 1.8 |
| 2017 | 5.7°C | 1.9°C | -2.0°C | 16.4°C | -10.0°C | 20 mm | 75% | 2.7 m/s | 1.9 |
| 2016 | 6.9°C | 2.8°C | -1.3°C | 17.6°C | -9.8°C | 69 mm | 77% | 3 m/s | 1.9 |
| 2015 🔥 | 13.2°C | 9.2°C | 5.1°C | 20.7°C | -3.4°C | 116 mm | 88% | 2.4 m/s | 1.7 |
| 2014 | 7.3°C | 3.6°C | -0.1°C | 17.0°C | -3.9°C | 91 mm | 85% | 2.7 m/s | 1.7 |
| 2013 | 6.8°C | 2.7°C | -1.4°C | 20.4°C | -10.6°C | 129 mm | 88% | 2.5 m/s | 1.8 |
| 2012 | 9.1°C | 5.1°C | 1.2°C | 19.6°C | -4.9°C | 91 mm | 86% | 2.8 m/s | 1.8 |
| 2011 | 9.5°C | 5.1°C | 0.7°C | 15.6°C | -3.6°C | 106 mm | 85% | 2.6 m/s | 2 |
| 2010 | 2.3°C | -1.0°C | -4.3°C | 16.8°C | -8.3°C | 53 mm | 79% | 3.7 m/s | 2 |
| 2009 | 4.6°C | 0.7°C | -3.2°C | 17.7°C | -11.2°C | 179 mm | 86% | 3.1 m/s | 1.9 |
| 2008 | 6.8°C | 2.7°C | -1.3°C | 17.5°C | -9.0°C | 95 mm | 82% | 3.2 m/s | 1.7 |
| 2007 | 6.7°C | 3.1°C | -0.5°C | 15.8°C | -6.5°C | 104 mm | 84% | 2.8 m/s | 1.6 |
| 2006 | 10.0°C | 5.5°C | 1.0°C | 22.4°C | -4.8°C | 48 mm | 82% | 2.6 m/s | 2.1 |
| 2005 | 4.2°C | 0.3°C | -3.7°C | 9.4°C | -10.0°C | 75 mm | 84% | 2.7 m/s | 2 |
| 2004 | 7.5°C | 3.0°C | -1.4°C | 15.8°C | -11.1°C | 71 mm | 81% | 3.1 m/s | 2.1 |
| 2003 | 5.3°C | 1.3°C | -2.6°C | 12.0°C | -9.2°C | 124 mm | 85% | 3.3 m/s | 2.2 |
| 2002 | 4.0°C | 0.2°C | -3.6°C | 14.1°C | -10.8°C | 120 mm | 85% | 2.9 m/s | 2 |
| 2001 | 10.3°C | 5.8°C | 1.3°C | 21.7°C | -7.7°C | 44 mm | 74% | 2.7 m/s | 2.2 |
| 2000 | 3.0°C | -1.1°C | -5.2°C | 16.3°C | -11.9°C | 72 mm | 75% | 3 m/s | 2.1 |
| 1999 | 7.7°C | 3.3°C | -1.1°C | 17.2°C | -6.9°C | 72 mm | 82% | 2.7 m/s | 1.9 |
| 1998 | 10.0°C | 5.5°C | 1.0°C | 23.8°C | -6.7°C | 47 mm | 71% | 2.6 m/s | 1.9 |
| 1997 | 6.7°C | 2.6°C | -1.4°C | 13.1°C | -6.6°C | 56 mm | 84% | 2.8 m/s | 2 |
| 1996 | 6.7°C | 3.1°C | -0.5°C | 14.8°C | -9.2°C | 158 mm | 90% | 3 m/s | 1.7 |
| 1995 | 2.2°C | -1.6°C | -5.5°C | 12.7°C | -11.9°C | 62 mm | 86% | 3.1 m/s | 2.2 |
| 1994 | 8.5°C | 4.3°C | 0.1°C | 18.6°C | -4.5°C | 52 mm | 82% | 2.7 m/s | 1.8 |
| 1993 | 5.1°C | 1.3°C | -2.4°C | 13.7°C | -9.0°C | 109 mm | 84% | 3 m/s | 1.8 |
| 1992 | 6.0°C | 2.2°C | -1.7°C | 17.0°C | -8.0°C | 112 mm | 84% | 3.1 m/s | 1.7 |
| 1991 | 7.3°C | 3.2°C | -0.9°C | 20.3°C | -8.6°C | 120 mm | 82% | 3 m/s | 2 |
| 1990 | 8.9°C | 4.3°C | -0.3°C | 18.0°C | -6.1°C | 125 mm | 84% | 3.1 m/s | 1.8 |
| 1989 ❄️ | -0.4°C | -4.7°C | -9.0°C | 9.5°C | -17.8°C | 51 mm | 85% | 3.1 m/s | 2 |
| 1988 | 5.1°C | 0.7°C | -3.7°C | 16.6°C | -12.1°C | 27 mm | 78% | 2.9 m/s | 2 |
| 1987 | 7.2°C | 3.2°C | -0.8°C | 14.2°C | -7.5°C | 68 mm | 82% | 3 m/s | 1.7 |
| 1986 | 6.6°C | 2.7°C | -1.3°C | 13.6°C | -5.5°C | 157 mm | 85% | 2.6 m/s | 1.9 |
| 1985 | 4.4°C | 0.4°C | -3.6°C | 13.1°C | -12.7°C | 23 mm | 80% | 3.1 m/s | 2 |
| 1984 | 9.8°C | 5.4°C | 1.1°C | 19.2°C | -5.6°C | 39 mm | 85% | 2.5 m/s | 1.5 |
| 1983 | 3.3°C | -0.6°C | -4.6°C | 15.1°C | -18.9°C | 170 mm | 84% | 3.2 m/s | — |
| 1982 | 8.9°C | 4.8°C | 0.7°C | 21.3°C | -6.2°C | 57 mm | 85% | 2.8 m/s | — |
| 1981 | 3.5°C | 0.0°C | -3.6°C | 12.9°C | -14.9°C | 90 mm | 85% | 3.1 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 6.7°C with lows near -1.4°C (mean 2.7°C), based on 45 years of NASA POWER data.
December averages 89 mm of rainfall in Washington, about average for rainfall. The wettest on record was 180 mm in 2023.
The hottest December reached 23.8°C in 1998. The coldest dipped to -18.9°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1.7°C. Daytime highs moved from 6°C to 8.1°C and overnight lows from -2°C to -0.7°C over the same span.
December is one of the cooler months of the year in Washington and about average for rainfall, so plan for around 6.7°C daytime highs and -1.4°C at night.
Not quite — December is the 3rd coolest month in Washington, averaging 2.7°C.
For December in Washington, pack warm layers and a jacket for chilly mornings, with typical highs of 6.7°C and lows of -1.4°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 83% — quite humid.
Average wind speed in December is 2.8 m/s. The windiest December on record averaged 3.7 m/s (2010).
The wettest December on record was 2023 with 180 mm. On average, December sees 89 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 December, 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 December specifically, along with year-by-year records and how the month has changed over the decades.
