Best time to visit Thunder Bay

Thunder Bay is a city of two halves. August scores 79 and December scores 25 — a 54-point swing, which is the difference between a holiday and an endurance test. The month you pick matters more here than almost anywhere. The good window runs June to September — 4 months within ten points of the best.

July is the warmest month at 24.7 °C and January the coolest at -8.5 °C — a 33.2 °C spread across the year. At the other end, 172 nights a year fall below freezing: the winter here is a real one.

There is a real wet season here. May, June, July and September carry the rain — up to 15 wet days in a month — while January, February, March and December drop as low as 6. That 9-day gap is the biggest single difference between a good month and a bad one in Thunder Bay, and it moves further than the temperature does.

Daylight runs from 8.4 hours in winter to 16.1 in summer, enough to notice on a sightseeing itinerary.

The three strongest months are August, July, September. The one to think twice about is December. Each month below has its own page with rainfall reliability, extremes, daylight and crowd levels.

Thunder Bay month by month