March is one of the cooler months of the year in Thunder Bay, with average highs near -0.7°C and lows around -10°C (mean -5.3°C). It is one of the drier months, averaging 30 mm of rainfall and 85% relative humidity across the period.
March is one of the cooler months of the year in Thunder Bay. Across 45 years of records, the warmest March in Thunder Bay was 2010 — when the month averaged 2°C — while the coldest was 2014 at -11.2°C. Typical March days reach -0.7°C with nights near -10°C. The long-term trend is warming, about 0.6°C per decade.
March is one of the drier months in Thunder Bay, averaging 30 mm of rainfall. The wettest March on record was 2004 with 68 mm, while the driest was 2018 at 8 mm.
Relative humidity in Thunder Bay during March averages 85%. The most humid Marchs were 1982 and 1984 at 98%, and the least humid was 2024 at 73%.
March receives about 3.3 kWh/m²/day of solar energy in Thunder Bay. The sunniest Marchs were 2018 and 2023 at 3.6 kWh/m²/day, and the cloudiest was 2004 at 2.7.
Average wind speed in Thunder Bay during March is 1.3 m/s. The windiest March was 1988 at 1.6 m/s, while the calmest were 2010, 2014 and 2016, among others at 1.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -6.9°C | -5.2°C | -5.7°C | -4.5°C | -4.1°C | +2.8°C |
| Avg High | -2.4°C | -0.5°C | -1.1°C | 0.3°C | 0.5°C | +2.9°C |
| Avg Low | -11.4°C | -10.0°C | -10.3°C | -9.2°C | -8.7°C | +2.7°C |
| Avg Rain | 35 mm | 27 mm | 38 mm | 24 mm | 27 mm | -8 mm |
March temperatures in Thunder Bay have risen by about 3.1°C between 1981–1985 and 2021–2025.
March has ranged from a record low of -30.2°C (1989) to a record high of 20.6°C (2012).
Rainfall in March is one of the drier months, averaging 30 mm, with a wettest year of 68 mm.
A quieter season to visit Thunder Bay
If your dates are flexible, the more temperate months of August and July tend to be the most comfortable for visiting Thunder Bay. That said, March — with days averaging -0.7°C and nights around -10°C (mean -5.3°C) and moderate rainfall (30 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 | 0.9°C | -4.2°C | -9.2°C | 11.2°C | -18.7°C | 27 mm | 76% | 1.5 m/s | 3.2 |
| 2024 | 1.6°C | -2.9°C | -7.3°C | 13.6°C | -16.1°C | 36 mm | 73% | 1.5 m/s | 3.5 |
| 2023 | -2.2°C | -6.3°C | -10.4°C | 5.8°C | -19.4°C | 22 mm | 87% | 1.5 m/s | 3.6 |
| 2022 | -1.7°C | -6.3°C | -10.9°C | 11.1°C | -23.6°C | 28 mm | 85% | 1.4 m/s | 3.3 |
| 2021 | 3.1°C | -1.8°C | -6.8°C | 11.5°C | -19.3°C | 23 mm | 74% | 1.4 m/s | 3.5 |
| 2020 | 1.5°C | -3.2°C | -7.8°C | 7.7°C | -17.5°C | 25 mm | 82% | 1.4 m/s | 3.2 |
| 2019 | -1.7°C | -6.3°C | -10.8°C | 10.0°C | -25.0°C | 21 mm | 84% | 1.2 m/s | 3.4 |
| 2018 | -0.6°C | -5.2°C | -9.8°C | 7.0°C | -14.2°C | 8 mm | 79% | 1.3 m/s | 3.6 |
| 2017 | -0.2°C | -5.0°C | -9.8°C | 12.3°C | -21.1°C | 25 mm | 76% | 1.5 m/s | 3.5 |
| 2016 | 2.2°C | -2.5°C | -7.2°C | 11.8°C | -22.3°C | 24 mm | 82% | 1.1 m/s | 3.3 |
| 2015 | -0.2°C | -5.0°C | -9.8°C | 7.2°C | -27.8°C | 18 mm | 80% | 1.3 m/s | 3.1 |
| 2014 ❄️ | -6.3°C | -11.2°C | -16.1°C | 6.1°C | -29.4°C | 29 mm | 94% | 1.1 m/s | 3 |
| 2013 | -2.7°C | -7.4°C | -12.0°C | 10.6°C | -23.5°C | 23 mm | 86% | 1.4 m/s | 3.2 |
| 2012 | 6.7°C | 1.9°C | -2.9°C | 20.6°C | -19.1°C | 47 mm | 81% | 1.2 m/s | 2.8 |
| 2011 | -1.9°C | -6.3°C | -10.8°C | 7.6°C | -21.6°C | 30 mm | 87% | 1.3 m/s | 3.2 |
| 2010 🔥 | 7.2°C | 2.0°C | -3.2°C | 18.3°C | -13.8°C | 16 mm | 79% | 1.1 m/s | 3.5 |
| 2009 | -1.2°C | -5.7°C | -10.2°C | 9.6°C | -24.3°C | 48 mm | 86% | 1.4 m/s | 3.2 |
| 2008 | -2.8°C | -8.1°C | -13.3°C | 5.8°C | -28.4°C | 22 mm | 89% | 1.3 m/s | 3.5 |
| 2007 | 1.2°C | -3.7°C | -8.6°C | 18.9°C | -25.5°C | 30 mm | 82% | 1.4 m/s | 3 |
| 2006 | 0.8°C | -3.8°C | -8.4°C | 10.8°C | -21.2°C | 47 mm | 85% | 1.3 m/s | 3.3 |
| 2005 | -3.8°C | -8.4°C | -12.9°C | 6.5°C | -23.1°C | 24 mm | 97% | 1.1 m/s | 3.5 |
| 2004 🌧️ | 0.4°C | -4.0°C | -8.3°C | 8.0°C | -18.4°C | 68 mm | 88% | 1.4 m/s | 2.7 |
| 2003 | -2.5°C | -7.0°C | -11.5°C | 11.7°C | -27.5°C | 30 mm | 84% | 1.2 m/s | 3 |
| 2002 | -4.6°C | -9.0°C | -13.4°C | 4.9°C | -25.1°C | 40 mm | 85% | 1.5 m/s | 3.4 |
| 2001 | -2.9°C | -7.2°C | -11.6°C | 1.8°C | -23.2°C | 33 mm | 98% | 1.1 m/s | 3 |
| 2000 | 4.4°C | -0.4°C | -5.2°C | 14.3°C | -16.5°C | 39 mm | 76% | 1.4 m/s | 3 |
| 1999 | 1.1°C | -3.5°C | -8.2°C | 11.0°C | -21.7°C | 40 mm | 82% | 1.4 m/s | 3.4 |
| 1998 | 1.4°C | -3.4°C | -8.2°C | 13.0°C | -18.8°C | 31 mm | 74% | 1.4 m/s | 3.4 |
| 1997 | -4.4°C | -8.8°C | -13.2°C | 0.6°C | -22.2°C | 40 mm | 97% | 1.2 m/s | 3.3 |
| 1996 | -6.2°C | -10.3°C | -14.4°C | 0.1°C | -29.4°C | 16 mm | 97% | 1.3 m/s | 3.3 |
| 1995 | 0.9°C | -3.7°C | -8.3°C | 13.8°C | -25.0°C | 12 mm | 80% | 1.3 m/s | 3.1 |
| 1994 | 1.9°C | -3.0°C | -7.9°C | 9.2°C | -15.8°C | 25 mm | 73% | 1.2 m/s | 3.3 |
| 1993 | 2.3°C | -3.3°C | -8.8°C | 14.6°C | -20.5°C | 10 mm | 76% | 1.1 m/s | 3.3 |
| 1992 | -1.5°C | -6.2°C | -11.0°C | 6.7°C | -22.9°C | 11 mm | 85% | 1.2 m/s | 3.5 |
| 1991 | -1.3°C | -6.0°C | -10.7°C | 8.1°C | -24.9°C | 57 mm | 90% | 1.3 m/s | 3.2 |
| 1990 | 0.9°C | -4.2°C | -9.2°C | 14.0°C | -22.9°C | 25 mm | 77% | 1.4 m/s | 3.3 |
| 1989 | -6.0°C | -10.6°C | -15.1°C | 6.3°C | -30.2°C | 27 mm | 95% | 1.2 m/s | 3 |
| 1988 | -2.2°C | -6.6°C | -11.1°C | 4.5°C | -21.5°C | 52 mm | 85% | 1.6 m/s | 3.4 |
| 1987 | 2.8°C | -2.0°C | -6.8°C | 12.8°C | -18.8°C | 11 mm | 75% | 1.3 m/s | 3.3 |
| 1986 | -1.6°C | -6.2°C | -10.8°C | 13.1°C | -25.8°C | 31 mm | 97% | 1.3 m/s | 3 |
| 1985 | 0.3°C | -4.7°C | -9.6°C | 9.6°C | -19.9°C | 34 mm | 84% | 1.4 m/s | 3.4 |
| 1984 | -6.3°C | -11.1°C | -15.8°C | 0.2°C | -29.4°C | 24 mm | 98% | 1.3 m/s | 3.5 |
| 1983 | -3.3°C | -6.8°C | -10.2°C | 2.0°C | -20.6°C | 44 mm | 96% | 1.4 m/s | — |
| 1982 | -5.0°C | -9.0°C | -13.1°C | 1.1°C | -26.3°C | 64 mm | 98% | 1.3 m/s | — |
| 1981 | -0.7°C | -5.2°C | -9.7°C | 8.1°C | -21.1°C | 30 mm | 94% | 1.4 m/s | — |
Actual recorded March data for each year, 1981–2025 — sourced from NASA POWER.
The average high in March is around -0.7°C with lows near -10°C (mean -5.3°C), based on 45 years of NASA POWER data.
March averages 30 mm of rainfall in Thunder Bay, one of the drier months. The wettest on record was 68 mm in 2004.
The hottest March reached 20.6°C in 2012. The coldest dipped to -30.2°C in 1989.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average March temperatures have risen by about 3.1°C. Daytime highs moved from -3°C to 0.3°C and overnight lows from -11.7°C to -8.9°C over the same span.
March is one of the cooler months of the year in Thunder Bay and one of the drier months, so plan for around -0.7°C daytime highs and -10°C at night.
Not quite — March is the 4th coolest month in Thunder Bay, averaging -5.3°C.
For March in Thunder Bay, pack warm layers and a jacket for chilly mornings, with typical highs of -0.7°C and lows of -10°C.
Relative humidity in March averages 85% — quite humid.
Average wind speed in March is 1.3 m/s. The windiest March on record averaged 1.6 m/s (1988).
The wettest March on record was 2004 with 68 mm. On average, March sees 30 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 Thunder Bay 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.
