December is one of the cooler months of the year in Brookline, with average highs near 3.4°C and lows around -4°C (mean -0.3°C). It is about average for rainfall, averaging 110 mm of rainfall and 86% relative humidity across the period.
December is one of the cooler months of the year in Brookline. Across 45 years of records, the warmest December in Brookline was 2015 — when the month averaged 5.5°C — while the coldest was 1989 at -8.2°C. Typical December days reach 3.4°C with nights near -4°C. The long-term trend is warming, about 0.5°C per decade.
December is about average for rainfall in Brookline, averaging 110 mm of rainfall. The wettest December on record was 2023 with 191 mm, while the driest was 1988 at 31 mm.
Relative humidity in Brookline during December averages 86%. The most humid December was 1981 at 95%, and the least humid was 2000 at 78%.
December receives about 1.5 kWh/m²/day of solar energy in Brookline. The sunniest Decembers were 1989 and 2018 at 1.8 kWh/m²/day, and the cloudiest were 2013, 2014 and 2015, among others at 1.3.
Average wind speed in Brookline during December is 0.8 m/s. The windiest Decembers were 2009, 2010 and 2025, among others at 0.9 m/s, while the calmest was 2015 at 0.6 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -1.9°C | 0.0°C | -0.4°C | 0.4°C | 0.7°C | +2.6°C |
| Avg High | 1.8°C | 3.7°C | 3.3°C | 3.9°C | 4.4°C | +2.6°C |
| Avg Low | -5.6°C | -3.7°C | -4.2°C | -3.2°C | -3.0°C | +2.6°C |
| Avg Rain | 88 mm | 109 mm | 111 mm | 116 mm | 129 mm | +41 mm |
December temperatures in Brookline have risen by about 2°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -20.3°C (1983) to a record high of 19.6°C (2001).
Rainfall in December is about average for rainfall, averaging 110 mm, with a wettest year of 191 mm.
A quieter season to visit Brookline
If your dates are flexible, the more temperate months of July and August tend to be the most comfortable for visiting Brookline. That said, December — with days averaging 3.4°C and nights around -4°C (mean -0.3°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 | 1.5°C | -2.4°C | -6.3°C | 14.0°C | -12.6°C | 79 mm | 82% | 0.9 m/s | — |
| 2024 | 3.9°C | 0.2°C | -3.5°C | 15.7°C | -13.0°C | 129 mm | 84% | 0.7 m/s | 1.7 |
| 2023 🌧️ | 6.6°C | 3.1°C | -0.4°C | 15.9°C | -6.1°C | 191 mm | 88% | 0.7 m/s | 1.5 |
| 2022 | 4.7°C | 1.0°C | -2.7°C | 13.5°C | -11.0°C | 149 mm | 84% | 0.8 m/s | 1.7 |
| 2021 | 5.5°C | 1.7°C | -2.0°C | 15.2°C | -7.5°C | 78 mm | 85% | 0.7 m/s | 1.4 |
| 2020 | 4.3°C | 0.6°C | -3.0°C | 16.2°C | -11.9°C | 149 mm | 86% | 0.8 m/s | 1.4 |
| 2019 | 2.9°C | -0.6°C | -4.0°C | 13.4°C | -13.0°C | 185 mm | 89% | 0.8 m/s | 1.4 |
| 2018 | 3.5°C | -0.3°C | -4.1°C | 14.8°C | -9.8°C | 101 mm | 86% | 0.7 m/s | 1.8 |
| 2017 | 0.7°C | -2.8°C | -6.3°C | 13.5°C | -19.9°C | 71 mm | 84% | 0.8 m/s | 1.5 |
| 2016 | 3.3°C | -0.4°C | -4.2°C | 13.6°C | -16.3°C | 94 mm | 84% | 0.8 m/s | 1.6 |
| 2015 🔥 | 9.2°C | 5.5°C | 1.8°C | 19.4°C | -4.5°C | 127 mm | 87% | 0.6 m/s | 1.3 |
| 2014 | 4.6°C | 1.5°C | -1.7°C | 13.4°C | -8.2°C | 154 mm | 88% | 0.7 m/s | 1.3 |
| 2013 | 1.8°C | -1.6°C | -4.9°C | 13.2°C | -18.8°C | 103 mm | 88% | 0.7 m/s | 1.3 |
| 2012 | 5.4°C | 1.8°C | -1.8°C | 14.4°C | -8.8°C | 142 mm | 86% | 0.8 m/s | 1.3 |
| 2011 | 6.0°C | 2.1°C | -1.9°C | 14.3°C | -8.4°C | 99 mm | 87% | 0.7 m/s | 1.7 |
| 2010 | 1.8°C | -1.6°C | -5.1°C | 13.8°C | -11.6°C | 84 mm | 82% | 0.9 m/s | 1.6 |
| 2009 | 1.8°C | -1.7°C | -5.1°C | 17.3°C | -13.6°C | 120 mm | 86% | 0.9 m/s | 1.5 |
| 2008 | 4.1°C | -0.3°C | -4.7°C | 14.0°C | -15.5°C | 158 mm | 88% | 0.8 m/s | 1.3 |
| 2007 | 1.7°C | -1.8°C | -5.4°C | 9.1°C | -15.8°C | 127 mm | 89% | 0.8 m/s | 1.3 |
| 2006 | 6.6°C | 3.0°C | -0.7°C | 17.6°C | -6.8°C | 58 mm | 86% | 0.7 m/s | 1.5 |
| 2005 | 1.9°C | -1.6°C | -5.1°C | 8.6°C | -13.7°C | 96 mm | 88% | 0.8 m/s | 1.6 |
| 2004 | 3.8°C | -0.3°C | -4.4°C | 13.7°C | -16.6°C | 114 mm | 86% | 0.8 m/s | 1.5 |
| 2003 | 3.7°C | -0.1°C | -4.0°C | 12.7°C | -11.8°C | 127 mm | 85% | 0.9 m/s | 1.5 |
| 2002 | 1.9°C | -1.6°C | -5.1°C | 13.1°C | -12.8°C | 131 mm | 87% | 0.9 m/s | 1.6 |
| 2001 | 6.3°C | 2.7°C | -0.9°C | 19.6°C | -6.3°C | 75 mm | 81% | 0.7 m/s | 1.7 |
| 2000 | 0.9°C | -2.8°C | -6.6°C | 15.5°C | -13.4°C | 103 mm | 78% | 0.9 m/s | 1.7 |
| 1999 | 4.7°C | 0.9°C | -3.0°C | 13.2°C | -12.4°C | 52 mm | 80% | 0.8 m/s | 1.6 |
| 1998 | 6.3°C | 2.0°C | -2.4°C | 19.5°C | -14.3°C | 41 mm | 81% | 0.7 m/s | 1.6 |
| 1997 | 3.2°C | -0.6°C | -4.3°C | 7.7°C | -13.3°C | 79 mm | 85% | 0.8 m/s | 1.6 |
| 1996 | 4.6°C | 1.5°C | -1.7°C | 12.3°C | -15.8°C | 175 mm | 91% | 0.7 m/s | 1.4 |
| 1995 | -0.5°C | -4.0°C | -7.5°C | 5.5°C | -11.5°C | 75 mm | 91% | 0.9 m/s | 1.7 |
| 1994 | 4.8°C | 0.9°C | -3.0°C | 14.7°C | -13.1°C | 154 mm | 85% | 0.8 m/s | 1.5 |
| 1993 | 3.0°C | -0.7°C | -4.3°C | 10.7°C | -15.5°C | 158 mm | 85% | 0.8 m/s | 1.4 |
| 1992 | 2.6°C | -0.9°C | -4.3°C | 8.8°C | -12.8°C | 157 mm | 86% | 0.9 m/s | 1.3 |
| 1991 | 3.0°C | -0.9°C | -4.8°C | 13.5°C | -12.1°C | 85 mm | 87% | 0.8 m/s | 1.5 |
| 1990 | 5.3°C | 1.6°C | -2.1°C | 16.9°C | -8.5°C | 119 mm | 84% | 0.8 m/s | 1.4 |
| 1989 ❄️ | -4.0°C | -8.2°C | -12.4°C | 3.9°C | -19.3°C | 37 mm | 83% | 0.9 m/s | 1.8 |
| 1988 | 1.9°C | -1.8°C | -5.5°C | 9.4°C | -16.1°C | 31 mm | 80% | 0.8 m/s | 1.5 |
| 1987 | 3.0°C | -0.3°C | -3.6°C | 10.1°C | -16.0°C | 64 mm | 86% | 0.8 m/s | 1.5 |
| 1986 | 3.1°C | -0.5°C | -4.1°C | 13.6°C | -11.2°C | 183 mm | 85% | 0.8 m/s | 1.6 |
| 1985 | 1.0°C | -3.0°C | -7.1°C | 11.3°C | -14.4°C | 36 mm | 84% | 0.8 m/s | 1.6 |
| 1984 | 4.8°C | 0.9°C | -2.9°C | 12.3°C | -11.3°C | 90 mm | 86% | 0.7 m/s | 1.3 |
| 1983 | 1.3°C | -2.5°C | -6.3°C | 11.4°C | -20.3°C | 157 mm | 87% | 0.8 m/s | — |
| 1982 | 5.0°C | 1.2°C | -2.6°C | 17.9°C | -13.5°C | 39 mm | 84% | 0.7 m/s | — |
| 1981 | 0.0°C | -3.2°C | -6.3°C | 8.8°C | -18.6°C | 155 mm | 95% | 0.8 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 3.4°C with lows near -4°C (mean -0.3°C), based on 45 years of NASA POWER data.
December averages 110 mm of rainfall in Brookline, about average for rainfall. The wettest on record was 191 mm in 2023.
The hottest December reached 19.6°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°C. Daytime highs moved from 2.4°C to 4.4°C and overnight lows from -5°C to -3°C over the same span.
December is one of the cooler months of the year in Brookline and about average for rainfall, so plan for around 3.4°C daytime highs and -4°C at night.
Not quite — December is the 3rd coolest month in Brookline, averaging -0.3°C.
For December in Brookline, pack warm layers and a jacket for chilly mornings, with typical highs of 3.4°C and lows of -4°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 86% — quite humid.
Average wind speed in December is 0.8 m/s. The windiest December on record averaged 0.9 m/s (1989).
The wettest December on record was 2023 with 191 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 Brookline 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.
