December is one of the cooler months of the year in Richland, with average highs near 3.7°C and lows around -3.1°C (mean 0.3°C). It is a relatively wet time of year, averaging 40 mm of rainfall and 83% relative humidity across the period.
December is one of the cooler months of the year in Richland. Across 45 years of records, the warmest December in Richland was 2025 — when the month averaged 4.4°C — while the coldest was 1983 at -5.8°C. Typical December days reach 3.7°C with nights near -3.1°C. The long-term trend is warming, about 0.7°C per decade.
December is a relatively wet time of year in Richland, averaging 40 mm of rainfall. The wettest December on record was 1996 with 101 mm, while the driest was 2013 at 14 mm.
Relative humidity in Richland during December averages 83%. The most humid December was 1985 at 91%, and the least humid was 1990 at 71%.
December receives about 1 kWh/m²/day of solar energy in Richland. The sunniest December was 1985 at 1.3 kWh/m²/day, and the cloudiest were 2022, 2023 and 2024, among others at 0.9.
Average wind speed in Richland during December is 2.1 m/s. The windiest December was 1990 at 2.9 m/s, while the calmest were 1989, 2011 and 2019, among others at 1.5 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -1.4°C | 0.3°C | 0.5°C | 0.9°C | 1.6°C | +3°C |
| Avg High | 2.0°C | 3.9°C | 3.9°C | 4.3°C | 4.9°C | +2.9°C |
| Avg Low | -4.9°C | -3.2°C | -2.9°C | -2.4°C | -1.8°C | +3.1°C |
| Avg Rain | 36 mm | 41 mm | 41 mm | 37 mm | 48 mm | +12 mm |
December temperatures in Richland have risen by about 4.4°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -22.7°C (1983) to a record high of 19.2°C (2021).
Rainfall in December is a relatively wet time of year, averaging 40 mm, with a wettest year of 101 mm.
A quieter season to visit Richland
If your dates are flexible, the more temperate months of August and June tend to be the most comfortable for visiting Richland. That said, December — with days averaging 3.7°C and nights around -3.1°C (mean 0.3°C) and moderate rainfall (40 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 🔥 | 8.1°C | 4.4°C | 0.7°C | 18.6°C | -5.3°C | 50 mm | 86% | 2.8 m/s | — |
| 2024 | 3.9°C | 1.1°C | -1.6°C | 10.0°C | -5.2°C | 69 mm | 90% | 2 m/s | 0.9 |
| 2023 | 5.8°C | 2.8°C | -0.2°C | 13.7°C | -4.3°C | 57 mm | 90% | 1.6 m/s | 0.9 |
| 2022 | 1.6°C | -2.0°C | -5.7°C | 9.8°C | -16.7°C | 49 mm | 84% | 2.2 m/s | 0.9 |
| 2021 | 4.5°C | 1.0°C | -2.6°C | 19.2°C | -12.5°C | 32 mm | 77% | 2.6 m/s | 1.1 |
| 2020 | 5.7°C | 2.2°C | -1.4°C | 15.9°C | -4.4°C | 31 mm | 84% | 2 m/s | 1 |
| 2019 | 5.5°C | 2.4°C | -0.7°C | 13.2°C | -3.4°C | 25 mm | 85% | 1.5 m/s | 0.9 |
| 2018 | 5.9°C | 2.4°C | -1.2°C | 13.2°C | -7.6°C | 39 mm | 81% | 2.2 m/s | 1 |
| 2017 | 2.3°C | -0.8°C | -3.8°C | 9.2°C | -9.7°C | 34 mm | 83% | 2 m/s | 0.9 |
| 2016 | 1.9°C | -1.5°C | -5.0°C | 11.1°C | -13.5°C | 30 mm | 79% | 2.5 m/s | 1.2 |
| 2015 | 5.0°C | 1.6°C | -1.8°C | 16.9°C | -10.6°C | 75 mm | 84% | 2.4 m/s | 0.9 |
| 2014 | 6.1°C | 2.4°C | -1.3°C | 13.6°C | -9.6°C | 38 mm | 80% | 2.2 m/s | 1 |
| 2013 | 1.9°C | -1.1°C | -4.1°C | 9.7°C | -13.4°C | 14 mm | 79% | 1.9 m/s | 1.2 |
| 2012 | 5.7°C | 2.5°C | -0.6°C | 12.9°C | -5.4°C | 43 mm | 83% | 2.4 m/s | 0.9 |
| 2011 | 4.0°C | 0.4°C | -3.1°C | 11.3°C | -7.7°C | 15 mm | 81% | 1.5 m/s | 1.1 |
| 2010 | 4.2°C | 0.9°C | -2.3°C | 12.1°C | -11.0°C | 60 mm | 85% | 2.2 m/s | 0.9 |
| 2009 | 1.1°C | -2.3°C | -5.6°C | 8.4°C | -12.4°C | 31 mm | 72% | 1.8 m/s | 1.1 |
| 2008 | 1.8°C | -1.8°C | -5.3°C | 12.3°C | -13.3°C | 40 mm | 79% | 2.5 m/s | 1 |
| 2007 | 4.7°C | 1.2°C | -2.2°C | 15.4°C | -7.1°C | 31 mm | 82% | 2.4 m/s | 1 |
| 2006 | 3.4°C | 0.2°C | -2.9°C | 11.9°C | -8.2°C | 48 mm | 85% | 1.9 m/s | 0.9 |
| 2005 | 1.8°C | -1.3°C | -4.5°C | 8.6°C | -13.1°C | 69 mm | 87% | 1.8 m/s | 0.9 |
| 2004 | 6.9°C | 3.1°C | -0.8°C | 15.2°C | -4.1°C | 21 mm | 82% | 2 m/s | 1 |
| 2003 | 5.1°C | 1.8°C | -1.5°C | 10.9°C | -5.3°C | 49 mm | 84% | 1.9 m/s | 0.9 |
| 2002 | 6.8°C | 3.1°C | -0.5°C | 16.5°C | -3.4°C | 68 mm | 83% | 2.1 m/s | 0.9 |
| 2001 | 5.1°C | 1.4°C | -2.2°C | 11.2°C | -6.6°C | 35 mm | 81% | 2.7 m/s | 1.1 |
| 2000 | 2.3°C | -0.7°C | -3.7°C | 6.8°C | -9.8°C | 20 mm | 83% | 1.8 m/s | 1.1 |
| 1999 | 6.2°C | 2.5°C | -1.1°C | 12.8°C | -5.6°C | 26 mm | 83% | 2.6 m/s | 1.1 |
| 1998 | 4.6°C | 0.9°C | -2.7°C | 11.5°C | -14.3°C | 43 mm | 78% | 2.8 m/s | 0.9 |
| 1997 | 4.3°C | 1.0°C | -2.3°C | 9.0°C | -6.4°C | 17 mm | 86% | 1.8 m/s | 1 |
| 1996 🌧️ | 3.2°C | -0.3°C | -3.8°C | 11.2°C | -13.8°C | 101 mm | 87% | 2.5 m/s | 1 |
| 1995 | 3.9°C | 0.5°C | -2.8°C | 11.8°C | -8.4°C | 61 mm | 83% | 2.2 m/s | 1 |
| 1994 | 3.8°C | 0.4°C | -3.1°C | 12.3°C | -9.9°C | 46 mm | 82% | 2.1 m/s | 1.2 |
| 1993 | 4.3°C | 0.8°C | -2.7°C | 15.6°C | -6.7°C | 38 mm | 84% | 1.9 m/s | 0.9 |
| 1992 | 1.8°C | -1.7°C | -5.2°C | 8.0°C | -14.1°C | 37 mm | 83% | 2.7 m/s | 1 |
| 1991 | 5.9°C | 2.6°C | -0.8°C | 12.2°C | -3.9°C | 21 mm | 84% | 2.2 m/s | 1.1 |
| 1990 | 0.7°C | -3.3°C | -7.3°C | 11.1°C | -22.2°C | 21 mm | 71% | 2.9 m/s | 1 |
| 1989 | 5.1°C | 1.6°C | -2.0°C | 18.0°C | -5.4°C | 15 mm | 82% | 1.5 m/s | 1 |
| 1988 | 3.8°C | 0.2°C | -3.3°C | 11.4°C | -10.8°C | 21 mm | 81% | 1.9 m/s | 1.1 |
| 1987 | 4.0°C | 0.2°C | -3.5°C | 14.4°C | -10.5°C | 58 mm | 80% | 2.4 m/s | 1.1 |
| 1986 | 2.8°C | -0.5°C | -3.9°C | 10.4°C | -8.3°C | 25 mm | 87% | 1.5 m/s | 1 |
| 1985 | -2.4°C | -5.5°C | -8.5°C | 3.2°C | -21.9°C | 21 mm | 91% | 1.6 m/s | 1.3 |
| 1984 | -0.2°C | -3.8°C | -7.4°C | 7.5°C | -18.6°C | 24 mm | 83% | 2.3 m/s | 1.1 |
| 1983 ❄️ | -2.5°C | -5.8°C | -9.1°C | 5.7°C | -22.7°C | 53 mm | 85% | 2.3 m/s | — |
| 1982 | 2.9°C | -0.5°C | -3.9°C | 14.2°C | -10.6°C | 59 mm | 86% | 2.2 m/s | — |
| 1981 | 4.7°C | 1.1°C | -2.5°C | 10.9°C | -10.1°C | 52 mm | 86% | 2.3 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 3.7°C with lows near -3.1°C (mean 0.3°C), based on 45 years of NASA POWER data.
December averages 40 mm of rainfall in Richland, a relatively wet time of year. The wettest on record was 101 mm in 1996.
The hottest December reached 19.2°C in 2021. The coldest dipped to -22.7°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 4.4°C. Daytime highs moved from 0.5°C to 4.8°C and overnight lows from -6.3°C to -1.9°C over the same span.
December is one of the cooler months of the year in Richland and a relatively wet time of year, so plan for around 3.7°C daytime highs and -3.1°C at night.
Yes — December is the coldest month of the year in Richland, averaging 0.3°C.
For December in Richland, pack warm layers and a jacket for chilly mornings, with typical highs of 3.7°C and lows of -3.1°C.
Relative humidity in December averages 83% — quite humid.
Average wind speed in December is 2.1 m/s. The windiest December on record averaged 2.9 m/s (1990).
The wettest December on record was 1996 with 101 mm. On average, December sees 40 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 Richland 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.
