March is one of the cooler months of the year in Sarnia, with average highs near 5.4°C and lows around -3.6°C (mean 0.9°C). It is one of the drier months, averaging 54 mm of rainfall and 79% relative humidity across the period.
March is one of the cooler months of the year in Sarnia. Across 45 years of records, the warmest March in Sarnia was 2012 — when the month averaged 7.1°C — while the coldest was 2014 at -4.6°C. Typical March days reach 5.4°C with nights near -3.6°C. The long-term trend is warming, about 0.3°C per decade.
March is one of the drier months in Sarnia, averaging 54 mm of rainfall. The wettest March on record was 2016 with 136 mm, while the driest was 2005 at 23 mm.
Relative humidity in Sarnia during March averages 79%. The most humid March was 1993 at 85%, and the least humid was 2021 at 71%.
March receives about 3.5 kWh/m²/day of solar energy in Sarnia. The sunniest March was 2021 at 4.6 kWh/m²/day, and the cloudiest were 2004 and 2008 at 2.9.
Average wind speed in Sarnia during March is 4.3 m/s. The windiest Marchs were 1985 and 2025 at 4.9 m/s, while the calmest were 1994 and 1995 at 3.6 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 0.4°C | 0.5°C | 1.2°C | 0.4°C | 2.6°C | +2.2°C |
| Avg High | 5.1°C | 4.9°C | 5.6°C | 4.7°C | 7.5°C | +2.4°C |
| Avg Low | -4.3°C | -3.9°C | -3.2°C | -4.0°C | -2.3°C | +2°C |
| Avg Rain | 54 mm | 51 mm | 45 mm | 62 mm | 59 mm | +5 mm |
March temperatures in Sarnia have risen by about 2.4°C between 1981–1985 and 2021–2025.
March has ranged from a record low of -22°C (2015) to a record high of 25.2°C (2012).
Rainfall in March is one of the drier months, averaging 54 mm, with a wettest year of 136 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, March — with days averaging 5.4°C and nights around -3.6°C (mean 0.9°C) and moderate rainfall (54 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 | 9.0°C | 3.5°C | -2.1°C | 19.1°C | -11.4°C | 56 mm | 75% | 4.9 m/s | 3.6 |
| 2024 | 7.7°C | 3.2°C | -1.3°C | 18.8°C | -6.9°C | 85 mm | 79% | 4.2 m/s | 3.3 |
| 2023 | 5.2°C | 1.1°C | -2.9°C | 12.2°C | -7.6°C | 61 mm | 78% | 4.4 m/s | 3.6 |
| 2022 | 5.9°C | 1.3°C | -3.3°C | 19.1°C | -13.4°C | 68 mm | 79% | 4.4 m/s | 3.5 |
| 2021 | 9.2°C | 3.5°C | -2.1°C | 18.9°C | -9.0°C | 38 mm | 71% | 4.5 m/s | 4.6 |
| 2020 | 7.7°C | 2.9°C | -1.9°C | 16.9°C | -8.9°C | 46 mm | 81% | 4.1 m/s | 3.3 |
| 2019 | 3.4°C | -0.9°C | -5.2°C | 15.6°C | -15.3°C | 66 mm | 78% | 4.1 m/s | 3.6 |
| 2018 | 2.4°C | -1.1°C | -4.6°C | 10.3°C | -9.7°C | 56 mm | 82% | 4.3 m/s | 3.8 |
| 2017 | 4.0°C | -0.1°C | -4.2°C | 18.2°C | -10.9°C | 98 mm | 79% | 4.7 m/s | 3.4 |
| 2016 🌧️ | 7.3°C | 2.7°C | -1.8°C | 17.7°C | -8.1°C | 136 mm | 83% | 3.8 m/s | 3.2 |
| 2015 | 2.6°C | -2.2°C | -6.9°C | 13.2°C | -22.0°C | 24 mm | 80% | 3.8 m/s | 3.7 |
| 2014 ❄️ | 0.2°C | -4.6°C | -9.5°C | 11.7°C | -20.1°C | 45 mm | 81% | 4.1 m/s | 3.5 |
| 2013 | 2.8°C | -0.6°C | -4.0°C | 13.0°C | -11.5°C | 27 mm | 81% | 4.3 m/s | 3.3 |
| 2012 🔥 | 11.9°C | 7.1°C | 2.3°C | 25.2°C | -5.7°C | 44 mm | 81% | 4.4 m/s | 3.7 |
| 2011 | 3.4°C | -0.7°C | -4.7°C | 15.2°C | -11.9°C | 97 mm | 83% | 4.1 m/s | 3.1 |
| 2010 | 8.9°C | 3.9°C | -1.1°C | 16.8°C | -5.2°C | 26 mm | 76% | 3.8 m/s | 4 |
| 2009 | 6.0°C | 1.5°C | -2.9°C | 16.6°C | -9.8°C | 74 mm | 76% | 4.1 m/s | 4 |
| 2008 | 3.5°C | -0.3°C | -4.1°C | 13.0°C | -13.3°C | 42 mm | 78% | 4.4 m/s | 2.9 |
| 2007 | 6.7°C | 2.1°C | -2.5°C | 22.1°C | -13.9°C | 52 mm | 77% | 4.6 m/s | 3.5 |
| 2006 | 5.6°C | 1.5°C | -2.6°C | 16.9°C | -9.1°C | 59 mm | 78% | 4.1 m/s | 3.6 |
| 2005 | 3.3°C | -1.0°C | -5.2°C | 15.5°C | -14.6°C | 23 mm | 80% | 3.7 m/s | 3.3 |
| 2004 | 6.7°C | 3.0°C | -0.8°C | 18.0°C | -6.6°C | 65 mm | 80% | 4.7 m/s | 2.9 |
| 2003 | 5.4°C | -0.3°C | -6.1°C | 20.1°C | -18.3°C | 42 mm | 79% | 3.9 m/s | 3.5 |
| 2002 | 4.5°C | 0.1°C | -4.2°C | 14.3°C | -11.6°C | 42 mm | 78% | 4.7 m/s | 3.2 |
| 2001 | 3.9°C | 0.1°C | -3.7°C | 11.0°C | -10.1°C | 27 mm | 77% | 3.8 m/s | 3.5 |
| 2000 | 9.9°C | 4.8°C | -0.3°C | 22.9°C | -5.5°C | 25 mm | 72% | 4.2 m/s | 3.5 |
| 1999 | 4.6°C | 0.1°C | -4.5°C | 19.1°C | -16.2°C | 28 mm | 75% | 4.5 m/s | 3.9 |
| 1998 | 5.7°C | 2.1°C | -1.4°C | 21.0°C | -11.7°C | 83 mm | 83% | 4.7 m/s | 3.3 |
| 1997 | 4.2°C | 0.0°C | -4.2°C | 16.4°C | -13.3°C | 68 mm | 81% | 4.4 m/s | 3.2 |
| 1996 | 2.2°C | -2.6°C | -7.4°C | 13.8°C | -15.5°C | 38 mm | 76% | 4.7 m/s | 3.7 |
| 1995 | 6.4°C | 1.4°C | -3.7°C | 19.5°C | -14.5°C | 34 mm | 78% | 3.6 m/s | 3.1 |
| 1994 | 4.8°C | 0.1°C | -4.6°C | 18.1°C | -11.5°C | 51 mm | 80% | 3.6 m/s | 3.7 |
| 1993 | 3.4°C | -0.5°C | -4.3°C | 15.6°C | -13.4°C | 38 mm | 85% | 3.8 m/s | 3.2 |
| 1992 | 4.3°C | -0.2°C | -4.7°C | 14.3°C | -13.3°C | 57 mm | 78% | 4 m/s | 3.6 |
| 1991 | 6.5°C | 2.2°C | -2.1°C | 17.2°C | -6.7°C | 64 mm | 80% | 4.8 m/s | 3.3 |
| 1990 | 6.4°C | 2.0°C | -2.4°C | 20.5°C | -13.6°C | 50 mm | 78% | 4 m/s | 3.2 |
| 1989 | 4.7°C | -0.5°C | -5.7°C | 20.1°C | -15.7°C | 48 mm | 78% | 4.3 m/s | 3.3 |
| 1988 | 5.0°C | 0.2°C | -4.6°C | 16.7°C | -10.5°C | 25 mm | 77% | 4.2 m/s | 3.2 |
| 1987 | 7.0°C | 2.3°C | -2.5°C | 20.1°C | -12.3°C | 40 mm | 78% | 3.9 m/s | 3.7 |
| 1986 | 6.3°C | 1.1°C | -4.2°C | 19.7°C | -18.5°C | 47 mm | 82% | 4.5 m/s | 3.6 |
| 1985 | 5.8°C | 1.3°C | -3.2°C | 14.8°C | -7.1°C | 94 mm | 81% | 4.9 m/s | 3.3 |
| 1984 | 1.4°C | -3.1°C | -7.6°C | 8.2°C | -17.2°C | 80 mm | 79% | 4.5 m/s | 3.5 |
| 1983 | 6.4°C | 2.0°C | -2.4°C | 15.4°C | -12.5°C | 49 mm | 81% | 4 m/s | — |
| 1982 | 3.7°C | -0.9°C | -5.4°C | 14.6°C | -14.6°C | 78 mm | 82% | 4.5 m/s | — |
| 1981 | 5.3°C | 1.2°C | -2.9°C | 17.7°C | -7.9°C | 25 mm | 75% | 4.4 m/s | — |
Actual recorded March data for each year, 1981–2025 — sourced from NASA POWER.
The average high in March is around 5.4°C with lows near -3.6°C (mean 0.9°C), based on 45 years of NASA POWER data.
March averages 54 mm of rainfall in Sarnia, one of the drier months. The wettest on record was 136 mm in 2016.
The hottest March reached 25.2°C in 2012. The coldest dipped to -22°C in 2015.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average March temperatures have risen by about 2.4°C. Daytime highs moved from 4.5°C to 7.4°C and overnight lows from -4.3°C to -2.3°C over the same span.
March is one of the cooler months of the year in Sarnia and one of the drier months, so plan for around 5.4°C daytime highs and -3.6°C at night.
Not quite — March is the 4th coolest month in Sarnia, averaging 0.9°C.
For March in Sarnia, pack warm layers and a jacket for chilly mornings, with typical highs of 5.4°C and lows of -3.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in March averages 79% — quite humid.
Average wind speed in March is 4.3 m/s. The windiest March on record averaged 4.9 m/s (1985).
The wettest March on record was 2016 with 136 mm. On average, March sees 54 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 March, 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 March specifically, along with year-by-year records and how the month has changed over the decades.
