December is one of the cooler months of the year in Snohomish, with average highs near 3.3°C and lows around -1.5°C (mean 0.9°C). It is a relatively wet time of year, averaging 256 mm of rainfall and 94% relative humidity across the period.
December is one of the cooler months of the year in Snohomish. Across 45 years of records, the warmest December in Snohomish was 2023 — when the month averaged 4.3°C — while the coldest was 1983 at -3.5°C. Typical December days reach 3.3°C with nights near -1.5°C. The long-term trend is warming, about 0.4°C per decade.
December is a relatively wet time of year in Snohomish, averaging 256 mm of rainfall. The wettest December on record was 2025 with 515 mm, while the driest was 1985 at 57 mm.
Relative humidity in Snohomish during December averages 94%. The most humid December was 2025 at 98%, and the least humid was 2009 at 86%.
December receives about 0.9 kWh/m²/day of solar energy in Snohomish. The sunniest Decembers were 1985 and 2009 at 1.1 kWh/m²/day, and the cloudiest were 2012, 2015 and 2019, among others at 0.7.
Average wind speed in Snohomish during December is 0.3 m/s. The windiest December was 1985 at 0.5 m/s, while the calmest were 2023, 2024 and 2025, among others at 0.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 0.2°C | 0.7°C | 1.0°C | 1.0°C | 1.7°C | +1.5°C |
| Avg High | 2.9°C | 3.0°C | 3.5°C | 3.3°C | 3.9°C | +1°C |
| Avg Low | -2.5°C | -1.7°C | -1.4°C | -1.2°C | -0.5°C | +2°C |
| Avg Rain | 211 mm | 288 mm | 223 mm | 251 mm | 331 mm | +120 mm |
December temperatures in Snohomish have risen by about 2.3°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -21.9°C (1990) to a record high of 12.8°C (2005).
Rainfall in December is a relatively wet time of year, averaging 256 mm, with a wettest year of 515 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.3°C per decade while lows rose 0.5°C per decade, narrowing the gap between day and night.
A quieter season to visit Snohomish
If your dates are flexible, the more temperate months of August and July tend to be the most comfortable for visiting Snohomish. That said, December — with days averaging 3.3°C and nights around -1.5°C (mean 0.9°C) and higher rainfall (256 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 🌧️ | 4.4°C | 2.6°C | 0.8°C | 11.0°C | -5.7°C | 515 mm | 98% | 0.3 m/s | — |
| 2024 | 4.0°C | 1.9°C | -0.1°C | 5.8°C | -4.4°C | 298 mm | 96% | 0.3 m/s | 0.9 |
| 2023 🔥 | 6.7°C | 4.3°C | 1.9°C | 11.3°C | -2.7°C | 312 mm | 93% | 0.3 m/s | 0.8 |
| 2022 | 1.8°C | -0.6°C | -3.1°C | 7.1°C | -17.5°C | 283 mm | 97% | 0.4 m/s | 0.8 |
| 2021 | 1.5°C | -0.8°C | -3.1°C | 10.1°C | -14.7°C | 294 mm | 97% | 0.3 m/s | 0.8 |
| 2020 | 5.1°C | 2.8°C | 0.5°C | 8.9°C | -4.0°C | 286 mm | 93% | 0.3 m/s | 0.9 |
| 2019 | 4.5°C | 2.6°C | 0.6°C | 7.6°C | -5.5°C | 270 mm | 96% | 0.3 m/s | 0.7 |
| 2018 | 4.4°C | 2.0°C | -0.4°C | 9.0°C | -5.4°C | 296 mm | 92% | 0.4 m/s | 0.9 |
| 2017 | 3.3°C | 0.6°C | -2.1°C | 7.2°C | -10.6°C | 218 mm | 92% | 0.4 m/s | 1 |
| 2016 | 0.5°C | -1.8°C | -4.1°C | 3.8°C | -11.5°C | 214 mm | 96% | 0.4 m/s | 0.9 |
| 2015 | 3.3°C | 1.3°C | -0.6°C | 11.0°C | -9.6°C | 396 mm | 96% | 0.4 m/s | 0.7 |
| 2014 | 5.1°C | 2.5°C | -0.1°C | 12.6°C | -12.8°C | 233 mm | 91% | 0.3 m/s | 1 |
| 2013 | 2.0°C | -0.6°C | -3.1°C | 6.6°C | -13.7°C | 152 mm | 90% | 0.4 m/s | 0.9 |
| 2012 | 2.5°C | 0.9°C | -0.7°C | 6.6°C | -6.2°C | 310 mm | 98% | 0.3 m/s | 0.7 |
| 2011 | 3.9°C | 1.3°C | -1.3°C | 8.0°C | -7.0°C | 146 mm | 92% | 0.4 m/s | 1 |
| 2010 | 3.4°C | 1.4°C | -0.7°C | 8.8°C | -10.7°C | 277 mm | 94% | 0.3 m/s | 0.8 |
| 2009 | 2.7°C | -0.3°C | -3.3°C | 8.7°C | -12.5°C | 120 mm | 86% | 0.3 m/s | 1.1 |
| 2008 | 1.2°C | -1.3°C | -3.8°C | 9.9°C | -18.3°C | 218 mm | 94% | 0.4 m/s | 0.8 |
| 2007 | 2.7°C | 0.6°C | -1.6°C | 11.1°C | -6.5°C | 368 mm | 96% | 0.3 m/s | 0.7 |
| 2006 | 3.1°C | 0.9°C | -1.2°C | 7.6°C | -8.3°C | 249 mm | 96% | 0.4 m/s | 0.8 |
| 2005 | 3.8°C | 1.4°C | -1.0°C | 12.8°C | -8.1°C | 231 mm | 93% | 0.4 m/s | 0.9 |
| 2004 | 5.4°C | 3.1°C | 0.8°C | 12.6°C | -2.5°C | 244 mm | 94% | 0.3 m/s | 0.8 |
| 2003 | 3.6°C | 1.5°C | -0.5°C | 6.9°C | -9.7°C | 189 mm | 95% | 0.3 m/s | 0.8 |
| 2002 | 5.6°C | 3.0°C | 0.5°C | 11.2°C | -3.7°C | 213 mm | 92% | 0.3 m/s | 0.7 |
| 2001 | 3.2°C | 0.7°C | -1.7°C | 5.4°C | -5.4°C | 269 mm | 95% | 0.3 m/s | 0.9 |
| 2000 | 3.3°C | 0.6°C | -2.0°C | 7.3°C | -8.5°C | 125 mm | 92% | 0.3 m/s | 0.9 |
| 1999 | 4.7°C | 2.6°C | 0.4°C | 8.1°C | -1.9°C | 297 mm | 94% | 0.3 m/s | 0.8 |
| 1998 | 2.1°C | 0.2°C | -1.8°C | 7.7°C | -13.3°C | 388 mm | 93% | 0.3 m/s | 0.8 |
| 1997 | 4.3°C | 2.0°C | -0.3°C | 7.7°C | -4.8°C | 201 mm | 93% | 0.3 m/s | 1 |
| 1996 | 2.0°C | -0.3°C | -2.6°C | 6.8°C | -10.4°C | 432 mm | 97% | 0.3 m/s | 0.8 |
| 1995 | 3.7°C | 1.2°C | -1.3°C | 6.8°C | -10.5°C | 282 mm | 92% | 0.3 m/s | 0.8 |
| 1994 | 2.7°C | 0.3°C | -2.0°C | 7.9°C | -11.5°C | 358 mm | 95% | 0.4 m/s | 0.9 |
| 1993 | 4.7°C | 2.0°C | -0.7°C | 9.4°C | -5.1°C | 227 mm | 89% | 0.4 m/s | 0.8 |
| 1992 | 1.1°C | -1.2°C | -3.5°C | 5.4°C | -11.3°C | 221 mm | 96% | 0.3 m/s | 0.9 |
| 1991 | 4.2°C | 2.3°C | 0.4°C | 7.4°C | -4.1°C | 206 mm | 94% | 0.3 m/s | 0.9 |
| 1990 | 0.2°C | -2.6°C | -5.5°C | 6.1°C | -21.9°C | 270 mm | 92% | 0.3 m/s | 0.8 |
| 1989 | 5.8°C | 3.2°C | 0.6°C | 11.7°C | -6.3°C | 195 mm | 92% | 0.4 m/s | 0.9 |
| 1988 | 4.0°C | 1.5°C | -1.0°C | 10.1°C | -9.5°C | 184 mm | 94% | 0.3 m/s | 0.8 |
| 1987 | 2.3°C | -0.6°C | -3.4°C | 8.2°C | -9.2°C | 269 mm | 95% | 0.4 m/s | 0.8 |
| 1986 | 4.3°C | 1.5°C | -1.3°C | 6.8°C | -5.9°C | 175 mm | 92% | 0.4 m/s | 0.8 |
| 1985 | 3.3°C | 0.2°C | -2.9°C | 7.5°C | -18.5°C | 57 mm | 90% | 0.5 m/s | 1.1 |
| 1984 | 0.5°C | -2.2°C | -5.0°C | 4.1°C | -14.8°C | 254 mm | 94% | 0.4 m/s | 1 |
| 1983 ❄️ | -0.5°C | -3.5°C | -6.4°C | 5.0°C | -18.9°C | 180 mm | 92% | 0.3 m/s | — |
| 1982 | 3.3°C | 0.6°C | -2.0°C | 9.0°C | -9.0°C | 307 mm | 94% | 0.4 m/s | — |
| 1981 | 2.8°C | 0.8°C | -1.3°C | 7.6°C | -9.0°C | 281 mm | 96% | 0.3 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 3.3°C with lows near -1.5°C (mean 0.9°C), based on 45 years of NASA POWER data.
December averages 256 mm of rainfall in Snohomish, a relatively wet time of year. The wettest on record was 515 mm in 2025.
The hottest December reached 12.8°C in 2005. The coldest dipped to -21.9°C in 1990.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 2.3°C. Daytime highs moved from 1.9°C to 3.7°C and overnight lows from -3.5°C to -0.7°C over the same span.
December is one of the cooler months of the year in Snohomish and a relatively wet time of year, so plan for around 3.3°C daytime highs and -1.5°C at night.
Yes — December is the coldest month of the year in Snohomish, averaging 0.9°C.
For December in Snohomish, pack warm layers and a jacket for chilly mornings, with typical highs of 3.3°C and lows of -1.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 94% — quite humid.
Average wind speed in December is 0.3 m/s. The windiest December on record averaged 0.5 m/s (1985).
The wettest December on record was 2025 with 515 mm. On average, December sees 256 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 Snohomish 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.
