Thunder Bay weather by month & the best time to visit
Canada · regional city · continental climate
The best time to visit Thunder Bay is August — its sunniest month (Sunshine Score 79/100), with July and June close behind. Thunder Bay averages about 1,985 hours of sunshine a year. Daytime highs around 24°C / 75°F and roughly 59 mm of rain in August.
When is the best time to visit Thunder Bay?
For sunshine, the best time to visit Thunder Bay is August, then July and June. The dullest month is January (0/100, 26 mm of rain). The full month-by-month picture is in the table below.
How sunny is Thunder Bay?
Thunder Bay gets a moderate 1,985 hours of sunshine a year. 79 Sunshine Score points separate August (79) from January (0), so the month you pick matters. It ranks #133 of 242 destinations in Canada for annual sunshine, below the national median of 2,024 hours. The year's 632 mm of rain spreads fairly evenly across the months, with no pronounced dry season.
Sunshine Score by month
| Month | Score | Day high | Night low | Rain | UV |
|---|---|---|---|---|---|
| January | 0 | -8° / 18°F | -17° / 1°F | 26 mm | 0 |
| February | 0 | -7° / 19°F | -16° / 3°F | 20 mm | 1 |
| March | 0 | 1° / 34°F | -9° / 16°F | 30 mm | 2 |
| April | 7 | 9° / 48°F | -2° / 28°F | 55 mm | 4 |
| May | 51 | 16° / 61°F | 4° / 39°F | 72 mm | 5 |
| June | 74 | 21° / 70°F | 10° / 50°F | 86 mm | 6 |
| July | 77 | 25° / 77°F | 13° / 55°F | 75 mm | 6 |
| August | 79 | 24° / 75°F | 13° / 55°F | 59 mm | 5 |
| September | 71 | 19° / 66°F | 9° / 48°F | 70 mm | 4 |
| October | 13 | 10° / 50°F | 2° / 36°F | 66 mm | 2 |
| November | 0 | 3° / 37°F | -4° / 25°F | 40 mm | 1 |
| December | 0 | -5° / 23°F | -12° / 10°F | 33 mm | 0 |
Nearest destinations
Head-to-head
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Thunder Bay: questions and answers
What kind of destination is Thunder Bay?
Thunder Bay is a regional city in Canada with a continental climate.
How many hours of sunshine does Thunder Bay get a year?
Thunder Bay gets about 1,985 hours of sunshine a year, at its best around August.
When is the best time to visit Thunder Bay?
The sunniest time to visit Thunder Bay is August, when the Sunshine Score peaks at 79/100 (with July and June close behind). Expect daytime highs around 24°C / 75°F.
What is the least sunny month in Thunder Bay?
January is the least sunny month in Thunder Bay, scoring 0/100 with about 26 mm of rain.
How strong is the sun in Thunder Bay?
The typical midday UV index in Thunder Bay peaks around 6 (high) in June, easing to about 0 (low) in January. Month-by-month midday UV values are in the UV column of the table on this page.
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