The best time to visit Thunder Bay
Month-by-month climate averages for Thunder Bay, Ontario, so you can pick your dates on data rather than guesswork.
The most comfortable time to visit Thunder Bay is usually July, August and September, when daytime highs sit in the pleasant 16-26°C range and the heaviest June rain is behind you.
Thunder Bay is warmest in July (highs near 21°C) and coldest in January (lows around -15°C), with roughly 674 mm of precipitation across the year and June the wettest month. The sweet spot for most visitors is July, August and September. Expect overnight frost in January, February, March, April, November and December.
These are long-run averages. For the actual days you are travelling, check the live Thunder Bay forecast - and note how much the models agree, because that tells you how much to trust it.
Thunder Bay weather by month
what to expect in Thunder Bay through the year, 1991-2020 averagesHere is Thunder Bay's typical weather in each month: the average daytime high and overnight low in °C, how each month feels, and the wettest month marked. Use it to plan any trip to Thunder Bay by season.