December is one of the cooler months of the year in West Chester, with average highs near 5.5°C and lows around -2.8°C (mean 1.4°C). It is about average for rainfall, averaging 98 mm of rainfall and 85% relative humidity across the period.
December is one of the cooler months of the year in West Chester. Across 45 years of records, the warmest December in West Chester was 2015 — when the month averaged 8.3°C — while the coldest was 1989 at -5.6°C. Typical December days reach 5.5°C with nights near -2.8°C. The long-term trend is warming, about 0.5°C per decade.
December is about average for rainfall in West Chester, averaging 98 mm of rainfall. The wettest December on record was 2023 with 228 mm, while the driest was 1998 at 25 mm.
Relative humidity in West Chester during December averages 85%. The most humid December was 1996 at 92%, and the least humid was 1998 at 74%.
December receives about 1.8 kWh/m²/day of solar energy in West Chester. The sunniest Decembers were 2000, 2001 and 2006, among others at 2 kWh/m²/day, and the cloudiest were 1992 and 2014 at 1.4.
Average wind speed in West Chester during December is 0.7 m/s. The windiest Decembers were 2003, 2009 and 2010 at 0.8 m/s, while the calmest were 2021, 2023 and 2024, among others at 0.6 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -0.1°C | 1.7°C | 0.8°C | 2.3°C | 2.1°C | +2.2°C |
| Avg High | 4.0°C | 5.9°C | 5.0°C | 6.3°C | 6.4°C | +2.4°C |
| Avg Low | -4.1°C | -2.5°C | -3.3°C | -1.7°C | -2.2°C | +1.9°C |
| Avg Rain | 76 mm | 98 mm | 107 mm | 102 mm | 112 mm | +37 mm |
December temperatures in West Chester have risen by about 1.9°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -19.6°C (1983) to a record high of 22.7°C (1998).
Rainfall in December is about average for rainfall, averaging 98 mm, with a wettest year of 228 mm.
A quieter season to visit West Chester
If your dates are flexible, the more temperate months of June and August tend to be the most comfortable for visiting West Chester. That said, December — with days averaging 5.5°C and nights around -2.8°C (mean 1.4°C) and higher rainfall (98 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 | 3.0°C | -0.9°C | -4.9°C | 12.8°C | -10.7°C | 70 mm | 80% | 0.7 m/s | — |
| 2024 | 6.1°C | 1.7°C | -2.7°C | 17.5°C | -13.0°C | 97 mm | 80% | 0.6 m/s | 1.9 |
| 2023 🌧️ | 8.5°C | 4.3°C | 0.2°C | 15.8°C | -5.1°C | 228 mm | 89% | 0.6 m/s | 1.6 |
| 2022 | 5.7°C | 1.2°C | -3.3°C | 14.5°C | -15.4°C | 123 mm | 85% | 0.7 m/s | 1.9 |
| 2021 | 9.6°C | 5.0°C | 0.4°C | 17.8°C | -6.3°C | 34 mm | 82% | 0.6 m/s | 1.8 |
| 2020 | 5.5°C | 1.3°C | -2.9°C | 16.4°C | -13.1°C | 123 mm | 88% | 0.7 m/s | 1.8 |
| 2019 | 5.7°C | 1.7°C | -2.2°C | 14.2°C | -10.9°C | 120 mm | 87% | 0.6 m/s | 1.6 |
| 2018 | 6.6°C | 2.6°C | -1.4°C | 16.7°C | -6.8°C | 159 mm | 89% | 0.6 m/s | 1.7 |
| 2017 | 4.0°C | -0.1°C | -4.2°C | 15.6°C | -14.0°C | 40 mm | 78% | 0.7 m/s | 1.8 |
| 2016 | 5.2°C | 1.1°C | -3.0°C | 15.3°C | -11.3°C | 76 mm | 81% | 0.7 m/s | 1.7 |
| 2015 🔥 | 12.5°C | 8.3°C | 4.2°C | 20.9°C | -4.0°C | 126 mm | 88% | 0.6 m/s | 1.5 |
| 2014 | 6.5°C | 2.6°C | -1.3°C | 16.2°C | -5.0°C | 87 mm | 86% | 0.6 m/s | 1.4 |
| 2013 | 5.0°C | 0.8°C | -3.3°C | 19.8°C | -12.5°C | 122 mm | 91% | 0.6 m/s | 1.6 |
| 2012 | 7.7°C | 3.8°C | 0.0°C | 18.2°C | -4.5°C | 109 mm | 88% | 0.7 m/s | 1.6 |
| 2011 | 8.2°C | 3.8°C | -0.6°C | 15.2°C | -5.2°C | 110 mm | 89% | 0.6 m/s | 1.9 |
| 2010 | 1.9°C | -1.6°C | -5.1°C | 16.4°C | -8.5°C | 67 mm | 80% | 0.8 m/s | 1.9 |
| 2009 | 3.8°C | 0.0°C | -3.8°C | 17.8°C | -13.1°C | 180 mm | 87% | 0.8 m/s | 1.9 |
| 2008 | 5.0°C | 0.8°C | -3.4°C | 16.1°C | -12.7°C | 140 mm | 87% | 0.7 m/s | 1.7 |
| 2007 | 4.3°C | 0.9°C | -2.5°C | 14.9°C | -8.5°C | 125 mm | 88% | 0.6 m/s | 1.5 |
| 2006 | 9.0°C | 4.3°C | -0.3°C | 20.8°C | -6.8°C | 60 mm | 85% | 0.6 m/s | 2 |
| 2005 | 3.0°C | -1.1°C | -5.3°C | 8.7°C | -16.1°C | 86 mm | 88% | 0.7 m/s | 1.9 |
| 2004 | 5.7°C | 1.3°C | -3.0°C | 14.8°C | -13.3°C | 86 mm | 86% | 0.7 m/s | 1.9 |
| 2003 | 4.6°C | 0.6°C | -3.3°C | 12.9°C | -10.5°C | 135 mm | 87% | 0.8 m/s | 1.9 |
| 2002 | 2.8°C | -1.0°C | -4.8°C | 13.5°C | -12.3°C | 123 mm | 88% | 0.7 m/s | 1.8 |
| 2001 | 9.5°C | 4.7°C | 0.0°C | 22.6°C | -9.5°C | 51 mm | 76% | 0.6 m/s | 2 |
| 2000 | 2.0°C | -2.2°C | -6.4°C | 16.9°C | -13.5°C | 89 mm | 77% | 0.7 m/s | 2 |
| 1999 | 6.6°C | 2.2°C | -2.3°C | 17.2°C | -10.4°C | 70 mm | 83% | 0.7 m/s | 1.9 |
| 1998 | 8.9°C | 4.2°C | -0.6°C | 22.7°C | -9.3°C | 25 mm | 74% | 0.6 m/s | 1.7 |
| 1997 | 5.8°C | 1.6°C | -2.6°C | 11.2°C | -8.6°C | 66 mm | 85% | 0.6 m/s | 2 |
| 1996 | 5.9°C | 2.4°C | -1.1°C | 13.9°C | -10.6°C | 196 mm | 92% | 0.7 m/s | 1.6 |
| 1995 | 0.7°C | -3.0°C | -6.7°C | 10.7°C | -13.8°C | 64 mm | 90% | 0.7 m/s | 2 |
| 1994 | 7.6°C | 3.0°C | -1.5°C | 17.1°C | -6.7°C | 67 mm | 84% | 0.7 m/s | 1.7 |
| 1993 | 4.4°C | 0.4°C | -3.7°C | 13.2°C | -11.5°C | 128 mm | 85% | 0.7 m/s | 1.6 |
| 1992 | 5.0°C | 1.1°C | -2.8°C | 15.7°C | -11.2°C | 114 mm | 86% | 0.7 m/s | 1.4 |
| 1991 | 6.3°C | 2.1°C | -2.2°C | 19.0°C | -9.8°C | 105 mm | 83% | 0.7 m/s | 1.8 |
| 1990 | 7.9°C | 3.2°C | -1.6°C | 17.5°C | -7.2°C | 140 mm | 85% | 0.7 m/s | 1.6 |
| 1989 ❄️ | -1.3°C | -5.6°C | -9.8°C | 8.2°C | -17.9°C | 35 mm | 83% | 0.7 m/s | 1.9 |
| 1988 | 4.0°C | -0.3°C | -4.6°C | 14.7°C | -14.5°C | 26 mm | 80% | 0.6 m/s | 1.8 |
| 1987 | 5.7°C | 1.8°C | -2.2°C | 13.5°C | -10.9°C | 49 mm | 85% | 0.7 m/s | 1.7 |
| 1986 | 5.3°C | 1.3°C | -2.7°C | 13.1°C | -6.6°C | 144 mm | 88% | 0.6 m/s | 1.8 |
| 1985 | 2.9°C | -1.1°C | -5.2°C | 10.8°C | -12.7°C | 29 mm | 83% | 0.7 m/s | 2 |
| 1984 | 7.7°C | 3.6°C | -0.6°C | 18.2°C | -6.4°C | 58 mm | 88% | 0.6 m/s | 1.7 |
| 1983 | 1.9°C | -2.0°C | -5.8°C | 14.3°C | -19.6°C | 194 mm | 88% | 0.7 m/s | — |
| 1982 | 7.6°C | 3.4°C | -0.8°C | 20.6°C | -10.3°C | 52 mm | 87% | 0.6 m/s | — |
| 1981 | 2.0°C | -1.7°C | -5.3°C | 9.9°C | -18.1°C | 94 mm | 89% | 0.7 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 5.5°C with lows near -2.8°C (mean 1.4°C), based on 45 years of NASA POWER data.
December averages 98 mm of rainfall in West Chester, about average for rainfall. The wettest on record was 228 mm in 2023.
The hottest December reached 22.7°C in 1998. The coldest dipped to -19.6°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1.9°C. Daytime highs moved from 4.4°C to 6.6°C and overnight lows from -3.5°C to -2.1°C over the same span.
December is one of the cooler months of the year in West Chester and about average for rainfall, so plan for around 5.5°C daytime highs and -2.8°C at night.
Not quite — December is the 3rd coolest month in West Chester, averaging 1.4°C.
For December in West Chester, pack warm layers and a jacket for chilly mornings, with typical highs of 5.5°C and lows of -2.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 85% — quite humid.
Average wind speed in December is 0.7 m/s. The windiest December on record averaged 0.8 m/s (2003).
The wettest December on record was 2023 with 228 mm. On average, December sees 98 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 West Chester 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.
