December is one of the cooler months of the year in Post Falls, with average highs near -0.4°C and lows around -7.2°C (mean -3.8°C). It is a relatively wet time of year, averaging 103 mm of rainfall and 94% relative humidity across the period.
December is one of the cooler months of the year in Post Falls. Across 45 years of records, the warmest December in Post Falls was 2025 — when the month averaged 1.5°C — while the coldest was 1983 at -10.3°C. Typical December days reach -0.4°C with nights near -7.2°C. The long-term trend is warming, about 0.8°C per decade.
December is a relatively wet time of year in Post Falls, averaging 103 mm of rainfall. The wettest December on record was 1996 with 223 mm, while the driest was 1985 at 34 mm.
Relative humidity in Post Falls during December averages 94%. The most humid December was 1985 at 99%, and the least humid was 2009 at 84%.
December receives about 0.9 kWh/m²/day of solar energy in Post Falls. The sunniest Decembers were 1985 and 2009 at 1.1 kWh/m²/day, and the cloudiest were 2015, 2019 and 2021, among others at 0.7.
Average wind speed in Post Falls during December is 1 m/s. The windiest December was 1990 at 1.4 m/s, while the calmest were 1989, 2000 and 2017, among others at 0.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -5.3°C | -4.0°C | -3.9°C | -3.3°C | -1.7°C | +3.6°C |
| Avg High | -1.6°C | -0.7°C | -0.4°C | -0.1°C | 1.3°C | +2.9°C |
| Avg Low | -9.1°C | -7.4°C | -7.4°C | -6.6°C | -4.8°C | +4.3°C |
| Avg Rain | 86 mm | 109 mm | 102 mm | 102 mm | 119 mm | +33 mm |
December temperatures in Post Falls have risen by about 5.1°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -36.9°C (1990) to a record high of 11.8°C (2021).
Rainfall in December is a relatively wet time of year, averaging 103 mm, with a wettest year of 223 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.6°C per decade while lows rose 1°C per decade, narrowing the gap between day and night.
A quieter season to visit Post Falls
If your dates are flexible, the more temperate months of August and July tend to be the most comfortable for visiting Post Falls. That said, December — with days averaging -0.4°C and nights around -7.2°C (mean -3.8°C) and higher rainfall (103 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 | 1.5°C | -1.4°C | 11.3°C | -9.4°C | 171 mm | 92% | 1.3 m/s | — |
| 2024 | 2.6°C | 0.0°C | -2.5°C | 6.3°C | -7.6°C | 116 mm | 95% | 0.9 m/s | 0.8 |
| 2023 | 2.8°C | 0.0°C | -2.8°C | 9.9°C | -9.4°C | 107 mm | 95% | 0.9 m/s | 0.9 |
| 2022 | -2.8°C | -6.6°C | -10.4°C | 1.5°C | -30.7°C | 118 mm | 98% | 0.9 m/s | 0.8 |
| 2021 | -1.1°C | -4.2°C | -7.3°C | 11.8°C | -19.0°C | 116 mm | 94% | 1.1 m/s | 0.7 |
| 2020 | 1.8°C | -1.2°C | -4.2°C | 7.2°C | -8.5°C | 87 mm | 91% | 0.9 m/s | 0.9 |
| 2019 | 1.8°C | -0.9°C | -3.7°C | 8.5°C | -8.5°C | 89 mm | 91% | 0.9 m/s | 0.7 |
| 2018 | 1.1°C | -2.0°C | -5.2°C | 5.7°C | -11.6°C | 104 mm | 92% | 1 m/s | 0.9 |
| 2017 | -1.0°C | -4.6°C | -8.2°C | 2.0°C | -20.8°C | 115 mm | 93% | 0.8 m/s | 0.9 |
| 2016 | -3.6°C | -7.7°C | -11.9°C | 2.2°C | -26.1°C | 77 mm | 96% | 1.1 m/s | 0.9 |
| 2015 | 0.4°C | -2.6°C | -5.6°C | 9.2°C | -15.9°C | 160 mm | 95% | 1.1 m/s | 0.7 |
| 2014 | 1.5°C | -1.7°C | -4.9°C | 8.4°C | -25.3°C | 110 mm | 93% | 1 m/s | 1 |
| 2013 | -1.8°C | -5.0°C | -8.2°C | 4.6°C | -21.7°C | 56 mm | 88% | 1 m/s | 1 |
| 2012 | 0.2°C | -2.8°C | -5.7°C | 7.2°C | -13.8°C | 121 mm | 95% | 1.2 m/s | 0.7 |
| 2011 | 1.1°C | -2.4°C | -5.9°C | 6.7°C | -10.9°C | 65 mm | 89% | 0.9 m/s | 1 |
| 2010 | -0.3°C | -3.8°C | -7.2°C | 3.0°C | -25.3°C | 125 mm | 97% | 0.9 m/s | 0.8 |
| 2009 | -2.5°C | -6.0°C | -9.5°C | 2.6°C | -19.8°C | 71 mm | 84% | 0.9 m/s | 1.1 |
| 2008 | -3.5°C | -7.2°C | -10.8°C | 3.1°C | -25.2°C | 132 mm | 94% | 1.1 m/s | 0.8 |
| 2007 | -0.6°C | -3.6°C | -6.7°C | 8.1°C | -12.8°C | 178 mm | 95% | 1.1 m/s | 0.8 |
| 2006 | 0.4°C | -2.9°C | -6.3°C | 6.6°C | -15.7°C | 80 mm | 93% | 1 m/s | 0.9 |
| 2005 | -1.8°C | -5.6°C | -9.4°C | 5.8°C | -24.2°C | 112 mm | 98% | 0.9 m/s | 0.9 |
| 2004 | 2.2°C | -0.7°C | -3.7°C | 6.0°C | -9.8°C | 77 mm | 93% | 0.9 m/s | 0.9 |
| 2003 | 0.3°C | -2.7°C | -5.6°C | 3.4°C | -16.1°C | 83 mm | 95% | 0.9 m/s | 0.8 |
| 2002 | 2.8°C | -0.4°C | -3.7°C | 8.4°C | -9.3°C | 108 mm | 91% | 1 m/s | 0.8 |
| 2001 | -0.7°C | -4.7°C | -8.8°C | 1.5°C | -15.3°C | 120 mm | 97% | 1.1 m/s | 0.9 |
| 2000 | -1.1°C | -5.3°C | -9.5°C | 2.3°C | -17.4°C | 55 mm | 96% | 0.8 m/s | 1 |
| 1999 | 1.2°C | -1.8°C | -4.7°C | 4.2°C | -9.3°C | 124 mm | 94% | 1 m/s | 0.8 |
| 1998 | -1.6°C | -4.1°C | -6.6°C | 4.1°C | -23.0°C | 153 mm | 91% | 1.3 m/s | 0.7 |
| 1997 | 0.5°C | -2.7°C | -6.0°C | 3.9°C | -13.5°C | 59 mm | 93% | 0.9 m/s | 1 |
| 1996 🌧️ | -2.0°C | -5.5°C | -9.1°C | 2.0°C | -21.4°C | 223 mm | 98% | 1.1 m/s | 0.8 |
| 1995 | 1.3°C | -2.2°C | -5.7°C | 7.4°C | -15.2°C | 99 mm | 90% | 1 m/s | 0.9 |
| 1994 | -0.6°C | -3.9°C | -7.2°C | 3.1°C | -17.4°C | 94 mm | 94% | 1 m/s | 1 |
| 1993 | 0.4°C | -2.5°C | -5.5°C | 6.3°C | -10.1°C | 78 mm | 93% | 0.9 m/s | 0.8 |
| 1992 | -2.6°C | -6.6°C | -10.7°C | 0.6°C | -19.5°C | 92 mm | 98% | 1.1 m/s | 0.8 |
| 1991 | 1.7°C | -1.4°C | -4.5°C | 3.6°C | -8.6°C | 76 mm | 93% | 1 m/s | 0.9 |
| 1990 | -5.3°C | -9.5°C | -13.7°C | 3.3°C | -36.9°C | 96 mm | 93% | 1.4 m/s | 0.8 |
| 1989 | 1.1°C | -2.2°C | -5.5°C | 8.5°C | -10.9°C | 68 mm | 93% | 0.8 m/s | 0.8 |
| 1988 | -0.4°C | -3.8°C | -7.2°C | 4.3°C | -20.3°C | 71 mm | 92% | 0.9 m/s | 1 |
| 1987 | 0.0°C | -3.6°C | -7.2°C | 8.8°C | -17.1°C | 118 mm | 93% | 1 m/s | 1 |
| 1986 | 0.1°C | -3.6°C | -7.3°C | 2.1°C | -12.8°C | 47 mm | 95% | 0.8 m/s | 1 |
| 1985 | -3.6°C | -7.7°C | -11.7°C | 0.3°C | -28.4°C | 34 mm | 99% | 0.8 m/s | 1.1 |
| 1984 | -4.2°C | -9.0°C | -13.9°C | 0.2°C | -23.8°C | 116 mm | 98% | 0.9 m/s | 1 |
| 1983 ❄️ | -5.9°C | -10.3°C | -14.7°C | 0.6°C | -31.7°C | 91 mm | 97% | 0.9 m/s | — |
| 1982 | -1.1°C | -4.3°C | -7.5°C | 6.1°C | -14.9°C | 108 mm | 95% | 1 m/s | — |
| 1981 | -0.1°C | -3.5°C | -7.0°C | 5.4°C | -18.3°C | 124 mm | 95% | 1 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around -0.4°C with lows near -7.2°C (mean -3.8°C), based on 45 years of NASA POWER data.
December averages 103 mm of rainfall in Post Falls, a relatively wet time of year. The wettest on record was 223 mm in 1996.
The hottest December reached 11.8°C in 2021. The coldest dipped to -36.9°C in 1990.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 5.1°C. Daytime highs moved from -3°C to 1.2°C and overnight lows from -11°C to -4.9°C over the same span.
December is one of the cooler months of the year in Post Falls and a relatively wet time of year, so plan for around -0.4°C daytime highs and -7.2°C at night.
Yes — December is the coldest month of the year in Post Falls, averaging -3.8°C.
For December in Post Falls, pack warm layers and a jacket for chilly mornings, with typical highs of -0.4°C and lows of -7.2°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 94% — quite humid.
Average wind speed in December is 1 m/s. The windiest December on record averaged 1.4 m/s (1990).
The wettest December on record was 1996 with 223 mm. On average, December sees 103 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 Post Falls 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.
