December is one of the cooler months of the year in Orillia, with average highs near -0.1°C and lows around -5.7°C (mean -2.9°C). It is about average for rainfall, averaging 46 mm of rainfall and 88% relative humidity across the period.
December is one of the cooler months of the year in Orillia. Across 45 years of records, the warmest December in Orillia was 2015 — when the month averaged 2.5°C — while the coldest was 1989 at -9.7°C. Typical December days reach -0.1°C with nights near -5.7°C. The long-term trend is warming, about 0.5°C per decade.
December is about average for rainfall in Orillia, averaging 46 mm of rainfall. The wettest December on record was 1983 with 110 mm, while the driest was 1994 at 12 mm.
Relative humidity in Orillia during December averages 88%. The most humid December was 1983 at 98%, and the least humid was 2021 at 82%.
December receives about 1 kWh/m²/day of solar energy in Orillia. The sunniest Decembers were 2001, 2003 and 2009, among others at 1.2 kWh/m²/day, and the cloudiest was 1984 at 0.7.
Average wind speed in Orillia during December is 2.5 m/s. The windiest Decembers were 2008 and 2025 at 2.9 m/s, while the calmest were 1994 and 2023 at 2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -4.3°C | -2.5°C | -3.5°C | -2.4°C | -1.4°C | +2.9°C |
| Avg High | -1.3°C | 0.4°C | -0.7°C | 0.2°C | 1.3°C | +2.6°C |
| Avg Low | -7.3°C | -5.4°C | -6.3°C | -5.0°C | -4.1°C | +3.2°C |
| Avg Rain | 50 mm | 33 mm | 64 mm | 39 mm | 40 mm | -10 mm |
December temperatures in Orillia have risen by about 2.5°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -25.4°C (1983) to a record high of 16.4°C (1982).
Rainfall in December is about average for rainfall, averaging 46 mm, with a wettest year of 110 mm.
A quieter season to visit Orillia
If your dates are flexible, the more temperate months of July and August tend to be the most comfortable for visiting Orillia. That said, December — with days averaging -0.1°C and nights around -5.7°C (mean -2.9°C) and moderate rainfall (46 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 | -1.2°C | -4.5°C | -7.8°C | 5.6°C | -13.2°C | 40 mm | 82% | 2.9 m/s | — |
| 2024 | 0.7°C | -1.8°C | -4.4°C | 8.0°C | -16.4°C | 41 mm | 84% | 2.4 m/s | 1 |
| 2023 | 3.3°C | 1.0°C | -1.4°C | 9.8°C | -7.1°C | 43 mm | 85% | 2 m/s | 1 |
| 2022 | 1.3°C | -1.5°C | -4.2°C | 8.4°C | -10.8°C | 42 mm | 84% | 2.7 m/s | 1 |
| 2021 | 2.4°C | -0.5°C | -3.3°C | 14.3°C | -8.4°C | 36 mm | 82% | 2.6 m/s | 1.1 |
| 2020 | 1.2°C | -1.3°C | -3.7°C | 7.0°C | -9.8°C | 40 mm | 83% | 2.6 m/s | 1.1 |
| 2019 | 0.5°C | -2.2°C | -4.8°C | 6.3°C | -13.9°C | 40 mm | 88% | 2.4 m/s | 1 |
| 2018 | 0.7°C | -2.3°C | -5.3°C | 7.5°C | -11.0°C | 45 mm | 88% | 2.1 m/s | 1 |
| 2017 | -2.8°C | -5.2°C | -7.6°C | 9.5°C | -16.7°C | 26 mm | 84% | 2.5 m/s | 1 |
| 2016 | 0.2°C | -2.2°C | -4.7°C | 7.9°C | -12.9°C | 43 mm | 85% | 2.8 m/s | 0.9 |
| 2015 🔥 | 5.2°C | 2.5°C | -0.2°C | 12.5°C | -7.6°C | 49 mm | 88% | 2.3 m/s | 1 |
| 2014 | 0.6°C | -2.0°C | -4.5°C | 6.3°C | -10.6°C | 33 mm | 85% | 2.3 m/s | 0.9 |
| 2013 | -3.2°C | -5.5°C | -7.8°C | 7.6°C | -15.6°C | 31 mm | 88% | 2.4 m/s | 0.9 |
| 2012 | 1.1°C | -1.4°C | -3.9°C | 11.8°C | -10.0°C | 46 mm | 88% | 2.3 m/s | 0.9 |
| 2011 | 1.7°C | -1.2°C | -4.0°C | 9.6°C | -13.2°C | 32 mm | 86% | 2.2 m/s | 1 |
| 2010 | -2.5°C | -5.0°C | -7.4°C | 7.8°C | -13.3°C | 46 mm | 93% | 2.6 m/s | 1.1 |
| 2009 | -1.1°C | -3.8°C | -6.4°C | 7.7°C | -14.5°C | 50 mm | 89% | 2.6 m/s | 1.2 |
| 2008 | -1.1°C | -4.4°C | -7.6°C | 9.5°C | -16.6°C | 85 mm | 91% | 2.9 m/s | 1 |
| 2007 | -1.5°C | -4.3°C | -7.1°C | 4.3°C | -17.0°C | 67 mm | 94% | 2.5 m/s | 0.9 |
| 2006 | 2.4°C | -0.2°C | -2.9°C | 8.2°C | -12.1°C | 63 mm | 92% | 2.6 m/s | 1.1 |
| 2005 | -1.9°C | -4.2°C | -6.4°C | 2.0°C | -14.4°C | 57 mm | 91% | 2.6 m/s | 1 |
| 2004 | -1.2°C | -4.7°C | -8.2°C | 7.5°C | -22.9°C | 96 mm | 93% | 2.7 m/s | 1 |
| 2003 | 0.5°C | -2.1°C | -4.8°C | 4.7°C | -10.4°C | 58 mm | 88% | 2.3 m/s | 1.2 |
| 2002 | -0.8°C | -3.9°C | -7.0°C | 3.5°C | -18.4°C | 47 mm | 93% | 2.4 m/s | 1 |
| 2001 | 2.1°C | -0.1°C | -2.3°C | 12.7°C | -10.0°C | 68 mm | 92% | 2.3 m/s | 1.2 |
| 2000 | -4.5°C | -7.4°C | -10.3°C | 2.3°C | -15.8°C | 52 mm | 94% | 2.6 m/s | 1.2 |
| 1999 | 1.0°C | -2.0°C | -4.9°C | 10.9°C | -14.3°C | 57 mm | 88% | 2.7 m/s | 0.9 |
| 1998 | 2.9°C | -0.2°C | -3.4°C | 14.2°C | -17.7°C | 61 mm | 87% | 2.7 m/s | 1 |
| 1997 | 0.7°C | -1.9°C | -4.5°C | 6.2°C | -14.8°C | 16 mm | 85% | 2.4 m/s | 1.1 |
| 1996 | 0.6°C | -1.9°C | -4.3°C | 8.3°C | -15.7°C | 47 mm | 90% | 2.2 m/s | 0.9 |
| 1995 | -3.3°C | -6.1°C | -8.8°C | 2.7°C | -15.0°C | 13 mm | 89% | 2.5 m/s | 1.2 |
| 1994 | 2.0°C | -1.2°C | -4.4°C | 8.5°C | -13.2°C | 12 mm | 85% | 2 m/s | 0.9 |
| 1993 | -0.7°C | -3.6°C | -6.6°C | 5.8°C | -19.1°C | 20 mm | 90% | 2.3 m/s | 1 |
| 1992 | 0.3°C | -2.2°C | -4.7°C | 6.2°C | -11.5°C | 25 mm | 88% | 2.5 m/s | 1 |
| 1991 | -0.2°C | -3.6°C | -6.9°C | 9.0°C | -16.8°C | 35 mm | 87% | 2.4 m/s | 1.1 |
| 1990 | 0.5°C | -2.7°C | -5.8°C | 6.5°C | -13.2°C | 40 mm | 87% | 2.6 m/s | 1.1 |
| 1989 ❄️ | -6.6°C | -9.7°C | -12.9°C | 2.3°C | -19.2°C | 16 mm | 88% | 2.3 m/s | 1.2 |
| 1988 | -0.8°C | -4.0°C | -7.2°C | 6.9°C | -16.4°C | 34 mm | 83% | 2.6 m/s | 1 |
| 1987 | 1.3°C | -1.5°C | -4.2°C | 7.7°C | -15.9°C | 22 mm | 83% | 2.5 m/s | 1.1 |
| 1986 | 0.1°C | -3.1°C | -6.4°C | 2.7°C | -16.9°C | 25 mm | 90% | 2.2 m/s | 1.1 |
| 1985 | -2.9°C | -5.3°C | -7.7°C | 6.1°C | -16.6°C | 30 mm | 91% | 2.5 m/s | 1 |
| 1984 | 1.1°C | -2.0°C | -5.1°C | 11.1°C | -16.8°C | 91 mm | 89% | 2.6 m/s | 0.7 |
| 1983 🌧️ | -4.9°C | -8.3°C | -11.7°C | 1.8°C | -25.4°C | 110 mm | 98% | 2.6 m/s | — |
| 1982 | 2.4°C | -1.0°C | -4.4°C | 16.4°C | -17.5°C | 100 mm | 91% | 2.4 m/s | — |
| 1981 | -1.3°C | -3.6°C | -6.0°C | 4.0°C | -13.3°C | 22 mm | 90% | 2.3 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around -0.1°C with lows near -5.7°C (mean -2.9°C), based on 45 years of NASA POWER data.
December averages 46 mm of rainfall in Orillia, about average for rainfall. The wettest on record was 110 mm in 1983.
The hottest December reached 16.4°C in 1982. The coldest dipped to -25.4°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 2.5°C. Daytime highs moved from -1.1°C to 1.3°C and overnight lows from -7°C to -4.2°C over the same span.
December is one of the cooler months of the year in Orillia and about average for rainfall, so plan for around -0.1°C daytime highs and -5.7°C at night.
Not quite — December is the 3rd coolest month in Orillia, averaging -2.9°C.
For December in Orillia, pack warm layers and a jacket for chilly mornings, with typical highs of -0.1°C and lows of -5.7°C.
Relative humidity in December averages 88% — quite humid.
Average wind speed in December is 2.5 m/s. The windiest December on record averaged 2.9 m/s (2008).
The wettest December on record was 1983 with 110 mm. On average, December sees 46 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 Orillia 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.
