December is one of the cooler months of the year in Sudbury, with average highs near -4.4°C and lows around -12.7°C (mean -8.5°C). It is about average for rainfall, averaging 56 mm of rainfall and 93% relative humidity across the period.
December is one of the cooler months of the year in Sudbury. Across 45 years of records, the warmest December in Sudbury was 2015 — when the month averaged -1.4°C — while the coldest was 1989 at -19.9°C. Typical December days reach -4.4°C with nights near -12.7°C. The long-term trend is warming, about 0.6°C per decade.
December is about average for rainfall in Sudbury, averaging 56 mm of rainfall. The wettest December on record was 2008 with 137 mm, while the driest was 1997 at 16 mm.
Relative humidity in Sudbury during December averages 93%. The most humid December was 1995 at 99%, and the least humid was 2021 at 87%.
December receives about 1 kWh/m²/day of solar energy in Sudbury. The sunniest Decembers were 1989 and 1995 at 1.2 kWh/m²/day, and the cloudiest were 1994, 1999 and 2015, among others at 0.8.
Average wind speed in Sudbury during December is 0.8 m/s. The windiest Decembers were 2004 and 2025 at 1 m/s, while the calmest were 2003, 2023 and 2024, among others at 0.7 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -10.7°C | -7.6°C | -9.0°C | -8.3°C | -6.4°C | +4.3°C |
| Avg High | -6.0°C | -3.5°C | -4.9°C | -4.3°C | -2.5°C | +3.5°C |
| Avg Low | -15.4°C | -11.8°C | -13.2°C | -12.3°C | -10.3°C | +5.1°C |
| Avg Rain | 62 mm | 43 mm | 69 mm | 54 mm | 47 mm | -14 mm |
December temperatures in Sudbury have risen by about 3.7°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -42.4°C (2004) to a record high of 11°C (2001).
Rainfall in December is about average for rainfall, averaging 56 mm, with a wettest year of 137 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.5°C per decade while lows rose 0.8°C per decade, narrowing the gap between day and night.
A quieter season to visit Sudbury
If your dates are flexible, the more temperate months of July and August tend to be the most comfortable for visiting Sudbury. That said, December — with days averaging -4.4°C and nights around -12.7°C (mean -8.5°C) and moderate rainfall (56 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 | -5.3°C | -10.3°C | -15.4°C | 5.4°C | -24.3°C | 61 mm | 91% | 1 m/s | — |
| 2024 | -2.9°C | -6.8°C | -10.6°C | 2.8°C | -23.4°C | 67 mm | 94% | 0.7 m/s | 1 |
| 2023 | 0.1°C | -3.0°C | -6.1°C | 6.6°C | -13.3°C | 18 mm | 89% | 0.7 m/s | 1 |
| 2022 | -2.5°C | -6.0°C | -9.4°C | 4.6°C | -20.4°C | 42 mm | 88% | 0.8 m/s | 1 |
| 2021 | -1.9°C | -6.0°C | -10.1°C | 10.5°C | -17.3°C | 50 mm | 87% | 0.9 m/s | 1 |
| 2020 | -2.6°C | -6.4°C | -10.1°C | 3.7°C | -21.1°C | 48 mm | 90% | 0.9 m/s | 1 |
| 2019 | -4.3°C | -8.6°C | -12.8°C | 1.5°C | -30.7°C | 39 mm | 97% | 0.8 m/s | 0.9 |
| 2018 | -4.0°C | -8.4°C | -12.8°C | 1.6°C | -23.8°C | 48 mm | 97% | 0.8 m/s | 0.9 |
| 2017 | -8.5°C | -12.8°C | -17.1°C | 8.5°C | -37.4°C | 62 mm | 93% | 0.8 m/s | 1.1 |
| 2016 | -3.8°C | -7.8°C | -11.7°C | 3.6°C | -28.1°C | 61 mm | 92% | 0.9 m/s | 1 |
| 2015 🔥 | 1.7°C | -1.4°C | -4.5°C | 9.0°C | -16.7°C | 110 mm | 92% | 0.9 m/s | 0.8 |
| 2014 | -3.7°C | -7.9°C | -12.0°C | 2.1°C | -28.6°C | 63 mm | 94% | 0.8 m/s | 1 |
| 2013 | -9.3°C | -13.7°C | -18.2°C | 1.9°C | -36.2°C | 42 mm | 95% | 0.8 m/s | 1 |
| 2012 | -3.3°C | -7.3°C | -11.4°C | 8.7°C | -22.8°C | 43 mm | 91% | 0.8 m/s | 0.9 |
| 2011 | -2.1°C | -6.2°C | -10.3°C | 5.4°C | -23.9°C | 41 mm | 87% | 0.8 m/s | 0.9 |
| 2010 | -5.7°C | -8.8°C | -11.9°C | 2.3°C | -22.1°C | 33 mm | 91% | 0.9 m/s | 0.9 |
| 2009 | -5.4°C | -9.5°C | -13.6°C | 3.2°C | -26.9°C | 58 mm | 96% | 0.8 m/s | 1 |
| 2008 🌧️ | -6.7°C | -11.4°C | -16.1°C | 2.4°C | -30.7°C | 137 mm | 98% | 0.9 m/s | 1 |
| 2007 | -5.7°C | -10.1°C | -14.4°C | 1.0°C | -27.4°C | 71 mm | 98% | 0.8 m/s | 0.9 |
| 2006 | -1.1°C | -4.1°C | -7.2°C | 3.5°C | -24.6°C | 83 mm | 94% | 0.8 m/s | 1 |
| 2005 | -5.2°C | -9.2°C | -13.2°C | -0.4°C | -20.8°C | 43 mm | 93% | 0.8 m/s | 1.1 |
| 2004 | -7.3°C | -12.5°C | -17.7°C | 3.2°C | -42.4°C | 76 mm | 95% | 1 m/s | 1 |
| 2003 | -3.1°C | -7.3°C | -11.5°C | 1.3°C | -27.5°C | 61 mm | 95% | 0.7 m/s | 1 |
| 2002 | -3.3°C | -7.4°C | -11.4°C | 2.5°C | -22.3°C | 50 mm | 94% | 0.9 m/s | 1 |
| 2001 | -0.5°C | -3.8°C | -7.0°C | 11.0°C | -19.1°C | 53 mm | 94% | 0.7 m/s | 1.1 |
| 2000 | -10.5°C | -15.1°C | -19.7°C | 0.1°C | -33.1°C | 55 mm | 99% | 0.8 m/s | 1.1 |
| 1999 | -2.3°C | -7.0°C | -11.7°C | 5.4°C | -26.3°C | 77 mm | 93% | 0.8 m/s | 0.8 |
| 1998 | -1.3°C | -5.5°C | -9.8°C | 8.8°C | -31.1°C | 45 mm | 91% | 0.8 m/s | 1 |
| 1997 | -2.8°C | -7.0°C | -11.2°C | 2.4°C | -29.8°C | 16 mm | 89% | 0.7 m/s | 1 |
| 1996 | -4.3°C | -8.2°C | -12.1°C | 2.4°C | -27.4°C | 70 mm | 97% | 0.7 m/s | 0.9 |
| 1995 | -9.4°C | -13.6°C | -17.8°C | 0.3°C | -28.0°C | 38 mm | 99% | 0.7 m/s | 1.2 |
| 1994 | -0.4°C | -3.8°C | -7.3°C | 4.9°C | -18.9°C | 20 mm | 90% | 0.7 m/s | 0.8 |
| 1993 | -3.5°C | -7.9°C | -12.3°C | 3.2°C | -35.5°C | 35 mm | 91% | 0.8 m/s | 0.9 |
| 1992 | -2.7°C | -6.6°C | -10.5°C | 4.8°C | -21.7°C | 44 mm | 90% | 0.9 m/s | 0.8 |
| 1991 | -4.8°C | -8.9°C | -13.0°C | 4.9°C | -24.4°C | 52 mm | 90% | 0.8 m/s | 1 |
| 1990 | -3.3°C | -7.9°C | -12.4°C | 3.5°C | -28.5°C | 38 mm | 90% | 0.9 m/s | 0.9 |
| 1989 ❄️ | -13.9°C | -19.9°C | -26.0°C | -2.3°C | -37.8°C | 31 mm | 99% | 0.7 m/s | 1.2 |
| 1988 | -5.4°C | -10.2°C | -15.1°C | 2.6°C | -25.5°C | 50 mm | 91% | 0.9 m/s | 0.9 |
| 1987 | -3.4°C | -7.8°C | -12.2°C | 2.7°C | -29.9°C | 65 mm | 98% | 0.8 m/s | 1.1 |
| 1986 | -3.4°C | -8.0°C | -12.5°C | 0.6°C | -29.8°C | 41 mm | 95% | 0.8 m/s | 0.9 |
| 1985 | -9.1°C | -14.1°C | -19.0°C | -0.2°C | -39.3°C | 58 mm | 99% | 0.7 m/s | 1 |
| 1984 | -3.5°C | -8.1°C | -12.7°C | 6.6°C | -25.1°C | 82 mm | 92% | 0.9 m/s | 0.9 |
| 1983 | -9.7°C | -15.0°C | -20.4°C | 0.1°C | -38.8°C | 74 mm | 98% | 0.8 m/s | — |
| 1982 | -1.1°C | -4.9°C | -8.7°C | 10.8°C | -21.7°C | 108 mm | 91% | 0.9 m/s | — |
| 1981 | -4.7°C | -8.3°C | -11.8°C | 1.9°C | -20.6°C | 46 mm | 94% | 0.8 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around -4.4°C with lows near -12.7°C (mean -8.5°C), based on 45 years of NASA POWER data.
December averages 56 mm of rainfall in Sudbury, about average for rainfall. The wettest on record was 137 mm in 2008.
The hottest December reached 11°C in 2001. The coldest dipped to -42.4°C in 2004.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 3.7°C. Daytime highs moved from -5.6°C to -2.5°C and overnight lows from -14.5°C to -10.3°C over the same span.
December is one of the cooler months of the year in Sudbury and about average for rainfall, so plan for around -4.4°C daytime highs and -12.7°C at night.
Not quite — December is the 3rd coolest month in Sudbury, averaging -8.5°C.
For December in Sudbury, pack warm layers and a jacket for chilly mornings, with typical highs of -4.4°C and lows of -12.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 93% — quite humid.
Average wind speed in December is 0.8 m/s. The windiest December on record averaged 1 m/s (2004).
The wettest December on record was 2008 with 137 mm. On average, December sees 56 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 Sudbury 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.
