Weather in Thunder Bay in January

The month to avoid. Of the twelve, January is the one to avoid. Highs sit at -8.5 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

January ranks 10 of 12 — near the bottom of Thunder Bay's year. August is the month that works, and the swing between the two is 54 points, which is a different holiday rather than a slightly better one.

Rain on 7 days, 0 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at -8.5 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 31 nights drop below freezing, so anything left outside stays frozen. Across the twenty years measured, the hottest January day reached 4 °C and the coldest night fell to -36.5 °C.

January is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest January on record still delivered 47 mm against 11 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 26 mm average is a reasonable planning figure, not a promise.

Wind is light at 5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 97%, which at -8.5 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How January sits in the year

This is a turning point in the year — December and February sit on opposite sides of it, so the month contains the change rather than following it.

Daylight in January

January sits at the dark end of Thunder Bay's year — 8.7 hours of daylight against 16.1 at midsummer, gaining 1 hours across the month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

An inland climate

Thunder Bay has no sea to moderate it, and it shows: 42 °C separates the hottest afternoon of the year from the coldest night. That is a genuinely continental range, and it means summer and winter here are barely the same place.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

January in Thunder Bay versus nearby

If Thunder Bay is one option among several, the nearby comparison is worth making. Minneapolis is close enough to be a coin toss — 2.9 °C warmer, 3 days less rain. Milwaukee is close enough to be a coin toss — 6.2 °C warmer, the same number of rain days.

So: January is a compromise. August is 52 points better and is what Thunder Bay is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Thunder Bay

See all twelve months in Thunder Bay, or where else to go in January.