December is one of the cooler months of the year in Morristown, with average highs near 8.9°C and lows around -1.1°C (mean 3.9°C). It is about average for rainfall, averaging 110 mm of rainfall and 82% relative humidity across the period.
December is one of the cooler months of the year in Morristown. Across 45 years of records, the warmest December in Morristown was 2015 — when the month averaged 10.2°C — while the coldest was 1989 at -2.4°C. Typical December days reach 8.9°C with nights near -1.1°C. The long-term trend is warming, about 0.7°C per decade.
December is about average for rainfall in Morristown, averaging 110 mm of rainfall. The wettest December on record was 1990 with 216 mm, while the driest was 1985 at 38 mm.
Relative humidity in Morristown during December averages 82%. The most humid December was 1982 at 88%, and the least humid was 1999 at 74%.
December receives about 1.9 kWh/m²/day of solar energy in Morristown. The sunniest December was 2006 at 2.4 kWh/m²/day, and the cloudiest was 1992 at 1.4.
Average wind speed in Morristown during December is 0.7 m/s. The windiest Decembers were 2023, 2024 and 2025, among others at 0.7 m/s, while the calmest were 2020, 2021 and 2022, 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 | 2.6°C | 3.9°C | 3.2°C | 4.8°C | 5.4°C | +2.8°C |
| Avg High | 7.5°C | 9.0°C | 8.4°C | 9.6°C | 10.8°C | +3.3°C |
| Avg Low | -2.4°C | -1.1°C | -1.8°C | 0.1°C | 0.1°C | +2.5°C |
| Avg Rain | 97 mm | 120 mm | 104 mm | 124 mm | 96 mm | 0 mm |
December temperatures in Morristown have risen by about 2.9°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -20.3°C (1983) to a record high of 23°C (2001).
Rainfall in December is about average for rainfall, averaging 110 mm, with a wettest year of 216 mm.
A quieter season to visit Morristown
If your dates are flexible, the more temperate months of June and September tend to be the most comfortable for visiting Morristown. That said, December — with days averaging 8.9°C and nights around -1.1°C (mean 3.9°C) and higher rainfall (110 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 | 9.9°C | 4.5°C | -1.0°C | 20.0°C | -10.8°C | 48 mm | 77% | 0.7 m/s | — |
| 2024 | 10.3°C | 5.1°C | -0.2°C | 19.9°C | -7.4°C | 109 mm | 79% | 0.7 m/s | 1.9 |
| 2023 | 11.5°C | 6.1°C | 0.7°C | 18.8°C | -6.9°C | 130 mm | 76% | 0.7 m/s | 2.1 |
| 2022 | 9.4°C | 4.3°C | -0.8°C | 19.4°C | -17.3°C | 108 mm | 84% | 0.6 m/s | 2 |
| 2021 | 15.3°C | 9.4°C | 3.5°C | 20.7°C | -5.3°C | 73 mm | 79% | 0.6 m/s | 1.9 |
| 2020 | 8.3°C | 3.2°C | -1.9°C | 17.0°C | -10.0°C | 110 mm | 83% | 0.6 m/s | 2 |
| 2019 | 11.3°C | 6.3°C | 1.4°C | 19.1°C | -5.8°C | 115 mm | 82% | 0.7 m/s | 2.1 |
| 2018 | 8.8°C | 4.7°C | 0.5°C | 18.7°C | -7.1°C | 163 mm | 86% | 0.6 m/s | 1.8 |
| 2017 | 8.3°C | 3.4°C | -1.4°C | 17.2°C | -12.3°C | 71 mm | 78% | 0.6 m/s | 1.9 |
| 2016 | 9.0°C | 4.0°C | -0.9°C | 19.5°C | -7.0°C | 125 mm | 80% | 0.7 m/s | 1.9 |
| 2015 🔥 | 14.8°C | 10.2°C | 5.6°C | 21.5°C | -5.5°C | 185 mm | 87% | 0.6 m/s | 1.8 |
| 2014 | 10.0°C | 5.3°C | 0.6°C | 18.4°C | -5.1°C | 97 mm | 85% | 0.6 m/s | 1.6 |
| 2013 | 9.2°C | 4.4°C | -0.4°C | 21.3°C | -6.6°C | 178 mm | 84% | 0.6 m/s | 1.9 |
| 2012 | 11.5°C | 6.3°C | 1.2°C | 20.9°C | -6.2°C | 127 mm | 81% | 0.7 m/s | 1.8 |
| 2011 | 11.1°C | 5.7°C | 0.4°C | 17.6°C | -6.0°C | 125 mm | 85% | 0.6 m/s | 2.1 |
| 2010 | 2.0°C | -2.0°C | -6.0°C | 12.5°C | -12.2°C | 58 mm | 83% | 0.7 m/s | 1.8 |
| 2009 | 5.9°C | 1.4°C | -3.0°C | 15.1°C | -9.2°C | 164 mm | 86% | 0.7 m/s | 1.8 |
| 2008 | 9.7°C | 4.4°C | -0.8°C | 18.1°C | -11.9°C | 165 mm | 82% | 0.7 m/s | 1.8 |
| 2007 | 12.1°C | 6.5°C | 0.9°C | 22.6°C | -6.5°C | 86 mm | 81% | 0.7 m/s | 1.8 |
| 2006 | 11.8°C | 6.0°C | 0.1°C | 19.3°C | -8.7°C | 64 mm | 78% | 0.7 m/s | 2.4 |
| 2005 | 6.0°C | 1.3°C | -3.4°C | 14.3°C | -7.3°C | 77 mm | 80% | 0.7 m/s | 2 |
| 2004 | 8.6°C | 3.3°C | -1.9°C | 19.9°C | -13.5°C | 114 mm | 80% | 0.7 m/s | 2.1 |
| 2003 | 7.1°C | 2.0°C | -3.0°C | 14.9°C | -6.8°C | 84 mm | 81% | 0.7 m/s | 2 |
| 2002 | 6.4°C | 2.0°C | -2.3°C | 13.2°C | -11.9°C | 133 mm | 87% | 0.7 m/s | 2 |
| 2001 | 11.6°C | 6.3°C | 1.0°C | 23.0°C | -9.6°C | 95 mm | 77% | 0.6 m/s | 2.3 |
| 2000 | 4.4°C | -0.8°C | -6.0°C | 13.9°C | -12.5°C | 59 mm | 78% | 0.7 m/s | 2 |
| 1999 | 10.5°C | 4.7°C | -1.1°C | 18.6°C | -7.4°C | 45 mm | 74% | 0.6 m/s | 2.1 |
| 1998 | 10.7°C | 5.2°C | -0.2°C | 22.3°C | -14.0°C | 159 mm | 83% | 0.6 m/s | 1.8 |
| 1997 | 7.0°C | 2.6°C | -1.9°C | 14.4°C | -9.8°C | 72 mm | 83% | 0.7 m/s | 1.8 |
| 1996 | 9.7°C | 4.4°C | -0.8°C | 19.2°C | -11.8°C | 101 mm | 83% | 0.7 m/s | 1.9 |
| 1995 | 6.1°C | 1.0°C | -4.1°C | 17.6°C | -15.3°C | 62 mm | 83% | 0.7 m/s | 2 |
| 1994 | 11.0°C | 5.7°C | 0.3°C | 17.7°C | -6.1°C | 54 mm | 82% | 0.6 m/s | 1.9 |
| 1993 | 6.6°C | 2.0°C | -2.5°C | 15.3°C | -10.6°C | 154 mm | 85% | 0.7 m/s | 1.8 |
| 1992 | 7.3°C | 2.9°C | -1.4°C | 16.8°C | -6.1°C | 142 mm | 86% | 0.6 m/s | 1.4 |
| 1991 | 9.8°C | 4.8°C | -0.3°C | 20.4°C | -7.2°C | 195 mm | 84% | 0.6 m/s | 2 |
| 1990 🌧️ | 10.8°C | 5.7°C | 0.7°C | 19.5°C | -8.1°C | 216 mm | 84% | 0.7 m/s | 1.7 |
| 1989 ❄️ | 2.1°C | -2.4°C | -7.0°C | 14.5°C | -19.2°C | 92 mm | 84% | 0.7 m/s | 2.2 |
| 1988 | 7.9°C | 2.7°C | -2.5°C | 17.1°C | -8.0°C | 90 mm | 79% | 0.7 m/s | 2.1 |
| 1987 | 10.3°C | 4.9°C | -0.6°C | 20.2°C | -6.5°C | 99 mm | 77% | 0.7 m/s | 1.7 |
| 1986 | 7.9°C | 3.2°C | -1.5°C | 16.8°C | -7.6°C | 105 mm | 85% | 0.6 m/s | 1.7 |
| 1985 | 5.6°C | 0.4°C | -4.8°C | 16.3°C | -13.8°C | 38 mm | 78% | 0.7 m/s | 2.1 |
| 1984 | 13.3°C | 7.9°C | 2.4°C | 20.1°C | -11.1°C | 62 mm | 86% | 0.6 m/s | 1.8 |
| 1983 | 5.9°C | 0.7°C | -4.5°C | 17.1°C | -20.3°C | 156 mm | 80% | 0.7 m/s | — |
| 1982 | 10.7°C | 6.0°C | 1.4°C | 20.5°C | -9.7°C | 124 mm | 88% | 0.6 m/s | — |
| 1981 | 4.1°C | -0.2°C | -4.5°C | 14.7°C | -13.5°C | 103 mm | 84% | 0.7 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 8.9°C with lows near -1.1°C (mean 3.9°C), based on 45 years of NASA POWER data.
December averages 110 mm of rainfall in Morristown, about average for rainfall. The wettest on record was 216 mm in 1990.
The hottest December reached 23°C in 2001. The coldest dipped to -20.3°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 2.9°C. Daytime highs moved from 7.9°C to 11.3°C and overnight lows from -2°C to 0.4°C over the same span.
December is one of the cooler months of the year in Morristown and about average for rainfall, so plan for around 8.9°C daytime highs and -1.1°C at night.
Not quite — December is the 2nd coolest month in Morristown, averaging 3.9°C.
For December in Morristown, pack warm layers and a jacket for chilly mornings, with typical highs of 8.9°C and lows of -1.1°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 82% — quite humid.
Average wind speed in December is 0.7 m/s. The windiest December on record averaged 0.7 m/s (1981).
The wettest December on record was 1990 with 216 mm. On average, December sees 110 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 Morristown 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.
