January is one of the cooler months of the year in Sarnia, with average highs near -1.8°C and lows around -8.5°C (mean -5.1°C). It is one of the drier months, averaging 50 mm of rainfall and 88% relative humidity across the period.
January is one of the cooler months of the year in Sarnia. Across 45 years of records, the warmest January in Sarnia was 2006 — when the month averaged 0°C — while the coldest were 1994 and 2014 at -10.3°C. Typical January days reach -1.8°C with nights near -8.5°C. The long-term trend is warming, about 0.5°C per decade.
January is one of the drier months in Sarnia, averaging 50 mm of rainfall. The wettest January on record was 1999 with 102 mm, while the driest was 2003 at 12 mm.
Relative humidity in Sarnia during January averages 88%. The most humid January was 2001 at 95%, and the least humid was 2003 at 80%.
January receives about 1.4 kWh/m²/day of solar energy in Sarnia. The sunniest January was 2022 at 2 kWh/m²/day, and the cloudiest were 2009, 2011 and 2017, among others at 1.2.
Average wind speed in Sarnia during January is 4.6 m/s. The windiest January was 1982 at 5.5 m/s, while the calmest were 2001, 2021 and 2023 at 3.7 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -6.5°C | -5.0°C | -4.5°C | -5.4°C | -3.7°C | +2.8°C |
| Avg High | -2.8°C | -1.6°C | -1.3°C | -2.1°C | -0.7°C | +2.1°C |
| Avg Low | -10.2°C | -8.4°C | -7.8°C | -8.8°C | -6.7°C | +3.5°C |
| Avg Rain | 34 mm | 56 mm | 45 mm | 61 mm | 55 mm | +21 mm |
January temperatures in Sarnia have risen by about 4°C between 1981–1985 and 2021–2025.
January has ranged from a record low of -27.3°C (1994) to a record high of 13.1°C (2008).
Rainfall in January is one of the drier months, averaging 50 mm, with a wettest year of 102 mm.
A quieter season to visit Sarnia
If your dates are flexible, the more temperate months of July and August tend to be the most comfortable for visiting Sarnia. That said, January — with days averaging -1.8°C and nights around -8.5°C (mean -5.1°C) and moderate rainfall (50 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 | -3.2°C | -6.6°C | -10.1°C | 2.6°C | -22.6°C | 35 mm | 85% | 5.2 m/s | 1.8 |
| 2024 | -0.6°C | -3.3°C | -5.9°C | 4.9°C | -18.4°C | 83 mm | 91% | 4.4 m/s | 1.5 |
| 2023 | 1.8°C | -0.9°C | -3.5°C | 8.1°C | -18.1°C | 61 mm | 87% | 3.7 m/s | 1.5 |
| 2022 | -3.3°C | -6.8°C | -10.3°C | 3.5°C | -15.7°C | 32 mm | 83% | 4.7 m/s | 2 |
| 2021 | 0.1°C | -2.5°C | -5.0°C | 5.1°C | -11.5°C | 34 mm | 87% | 3.7 m/s | 1.3 |
| 2020 | 1.0°C | -2.1°C | -5.3°C | 9.3°C | -14.6°C | 84 mm | 89% | 4.2 m/s | 1.3 |
| 2019 | -2.8°C | -6.3°C | -9.9°C | 7.7°C | -21.1°C | 92 mm | 87% | 4.9 m/s | 1.5 |
| 2018 | -2.3°C | -6.2°C | -10.0°C | 8.1°C | -25.0°C | 70 mm | 89% | 5 m/s | 1.5 |
| 2017 | 0.3°C | -2.5°C | -5.4°C | 7.8°C | -14.7°C | 97 mm | 88% | 4.1 m/s | 1.2 |
| 2016 | -0.9°C | -3.9°C | -6.8°C | 7.4°C | -13.1°C | 49 mm | 86% | 4.7 m/s | 1.5 |
| 2015 | -4.2°C | -8.1°C | -12.0°C | 1.7°C | -18.2°C | 52 mm | 87% | 4.4 m/s | 1.4 |
| 2014 | -5.9°C | -10.3°C | -14.7°C | 2.2°C | -23.6°C | 61 mm | 93% | 5 m/s | 1.4 |
| 2013 | -0.4°C | -3.6°C | -6.9°C | 10.9°C | -16.2°C | 81 mm | 85% | 4.8 m/s | 1.5 |
| 2012 | 0.9°C | -2.1°C | -5.1°C | 7.1°C | -13.5°C | 49 mm | 86% | 4.8 m/s | 1.4 |
| 2011 | -3.7°C | -6.6°C | -9.5°C | 6.4°C | -18.1°C | 43 mm | 87% | 4 m/s | 1.2 |
| 2010 | -1.6°C | -4.5°C | -7.3°C | 4.1°C | -14.0°C | 19 mm | 87% | 4.7 m/s | 1.5 |
| 2009 | -4.7°C | -8.3°C | -11.9°C | 0.8°C | -19.7°C | 30 mm | 89% | 4.2 m/s | 1.2 |
| 2008 | 0.7°C | -2.5°C | -5.6°C | 13.1°C | -14.1°C | 70 mm | 84% | 5.2 m/s | 1.5 |
| 2007 | 0.2°C | -3.0°C | -6.2°C | 9.5°C | -18.6°C | 54 mm | 87% | 4.6 m/s | 1.3 |
| 2006 🔥 | 2.9°C | 0.0°C | -2.8°C | 9.2°C | -8.1°C | 69 mm | 88% | 4.8 m/s | 1.5 |
| 2005 | -2.0°C | -5.5°C | -8.9°C | 11.7°C | -18.4°C | 69 mm | 87% | 4.4 m/s | 1.4 |
| 2004 | -4.2°C | -7.4°C | -10.6°C | 8.7°C | -17.7°C | 43 mm | 87% | 5.3 m/s | 1.5 |
| 2003 | -4.2°C | -7.3°C | -10.5°C | 4.3°C | -16.8°C | 12 mm | 80% | 5 m/s | 1.5 |
| 2002 | 1.7°C | -1.4°C | -4.5°C | 9.1°C | -10.6°C | 36 mm | 87% | 4.6 m/s | 1.6 |
| 2001 | -2.1°C | -5.4°C | -8.8°C | 1.4°C | -16.8°C | 27 mm | 95% | 3.7 m/s | 1.2 |
| 2000 | -1.0°C | -4.4°C | -7.9°C | 9.7°C | -14.9°C | 38 mm | 83% | 5.1 m/s | 1.5 |
| 1999 🌧️ | -2.9°C | -6.7°C | -10.5°C | 9.5°C | -21.8°C | 102 mm | 92% | 4.8 m/s | 1.5 |
| 1998 | 1.0°C | -2.0°C | -5.0°C | 8.7°C | -15.6°C | 69 mm | 90% | 4.2 m/s | 1.4 |
| 1997 | -2.2°C | -5.9°C | -9.6°C | 11.4°C | -19.0°C | 39 mm | 87% | 5.4 m/s | 1.4 |
| 1996 | -2.0°C | -5.4°C | -8.9°C | 10.3°C | -15.8°C | 46 mm | 83% | 4.8 m/s | 1.4 |
| 1995 | -0.6°C | -3.6°C | -6.7°C | 11.4°C | -15.2°C | 58 mm | 89% | 4.5 m/s | 1.2 |
| 1994 ❄️ | -6.5°C | -10.3°C | -14.0°C | 1.7°C | -27.3°C | 51 mm | 89% | 4.7 m/s | 1.4 |
| 1993 | -0.7°C | -4.0°C | -7.3°C | 9.4°C | -15.4°C | 74 mm | 87% | 4.6 m/s | 1.4 |
| 1992 | -1.1°C | -4.2°C | -7.3°C | 3.8°C | -19.5°C | 55 mm | 90% | 4.1 m/s | 1.4 |
| 1991 | -2.8°C | -6.5°C | -10.2°C | 2.0°C | -18.8°C | 31 mm | 89% | 4.7 m/s | 1.5 |
| 1990 | 1.7°C | -1.6°C | -4.9°C | 8.2°C | -9.8°C | 37 mm | 86% | 5 m/s | 1.2 |
| 1989 | 1.8°C | -2.0°C | -5.8°C | 12.0°C | -12.1°C | 30 mm | 83% | 5.2 m/s | 1.4 |
| 1988 | -2.2°C | -5.7°C | -9.1°C | 10.2°C | -18.4°C | 27 mm | 83% | 5.2 m/s | 1.3 |
| 1987 | -1.4°C | -4.5°C | -7.6°C | 3.3°C | -17.9°C | 38 mm | 88% | 4 m/s | 1.3 |
| 1986 | -2.5°C | -6.3°C | -10.0°C | 5.2°C | -17.8°C | 23 mm | 90% | 4.7 m/s | 1.3 |
| 1985 | -5.1°C | -9.0°C | -12.9°C | 1.6°C | -20.9°C | 52 mm | 93% | 4.7 m/s | 1.4 |
| 1984 | -5.7°C | -9.7°C | -13.7°C | 0.3°C | -25.4°C | 24 mm | 94% | 3.9 m/s | 1.4 |
| 1983 | -0.2°C | -3.3°C | -6.4°C | 5.7°C | -14.5°C | 24 mm | 84% | 4.4 m/s | — |
| 1982 | -5.8°C | -10.2°C | -14.6°C | 3.9°C | -26.3°C | 67 mm | 90% | 5.5 m/s | — |
| 1981 | -4.4°C | -7.8°C | -11.3°C | 4.6°C | -21.1°C | 20 mm | 92% | 4.1 m/s | — |
Actual recorded January data for each year, 1981–2025 — sourced from NASA POWER.
The average high in January is around -1.8°C with lows near -8.5°C (mean -5.1°C), based on 45 years of NASA POWER data.
January averages 50 mm of rainfall in Sarnia, one of the drier months. The wettest on record was 102 mm in 1999.
The hottest January reached 13.1°C in 2008. The coldest dipped to -27.3°C in 1994.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average January temperatures have risen by about 4°C. Daytime highs moved from -4.2°C to -1°C and overnight lows from -11.8°C to -7°C over the same span.
January is one of the cooler months of the year in Sarnia and one of the drier months, so plan for around -1.8°C daytime highs and -8.5°C at night.
Yes — January is the coldest month of the year in Sarnia, averaging -5.1°C.
For January in Sarnia, pack warm layers and a jacket for chilly mornings, with typical highs of -1.8°C and lows of -8.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in January averages 88% — quite humid.
Average wind speed in January is 4.6 m/s. The windiest January on record averaged 5.5 m/s (1982).
The wettest January on record was 1999 with 102 mm. On average, January sees 50 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 Sarnia behaves each January, 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 January specifically, along with year-by-year records and how the month has changed over the decades.
