Climate almanac
Thunder Bay
Ontario, Canada · 48.38°, -89.25°
What is the climate like in Thunder Bay?
The best time to visit Thunder Bay is typically July – August, with trip comfort peaking in July (7.0/10). Thunder Bay is warmest in July, when daily highs average 74°F (23°C), and coolest in February, when lows fall to about 3°F (-16°C). The wettest month is typically September and the driest is January; the year sees roughly 28 in (712 mm) of precipitation.
- Best time to visitJuly – August — comfort peaks in July (7.0/10)
- Warmest monthJuly — average high 74°F (23°C)
- Coolest monthFebruary — average low 3°F (-16°C)
- Wettest monthSeptember (3.2 in (81 mm))
- Driest monthJanuary (1.3 in (34 mm))
- Annual precipitation28 in (712 mm)
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)
- Records fromWelcome Island (aut), 10 km away (1967-2026)