Year-round weather and climate in Thunder Bay, Canada
Average temperatures in Thunder Bay run from an average low of -13°C9°F in January up to an average high of 22°C72°F in August. January is the driest month at 6 rainy days; April the wettest at 12 rainy days. Here is the annual climate data, so you know what you are packing for.
Good to know
- Population
- 109K
- Currency
- CAD
- Language
- English / French
- Time zone
- Thunder Bay
Best time to visit
For the warmest temperatures and best chance of outdoor activities, plan your trip around July, August, and September.
Rain character
Moderate Showers: Rainfall is standard and manageable. A compact travel umbrella or light rain jacket will easily get you through any wet days.
Day-to-night swing
Evening Chill: Temperatures drop by a noticeable <span class="val-c">9°C</span><span class="val-f">16°F</span> when the sun goes down. A light sweater or jacket is usually all you need for evening plans.
Seasonality Profile
Deep Continental: Dominated by long, freezing winters. Summers are brief but pleasantly mild.
Evening vibe
Cozy Indoor Culture: Evenings are generally crisp, damp, or sweltering. Nightlife centers around indoor venues.
Sightseeing stamina
All-Day Strolling: Weather is generally forgiving for long walking days. Comfortable sneakers are your most important packing item.
Average temperatures, sunshine, and rainfall
Average monthly weather in Thunder Bay, based on recent historical data. Essential insights on temperature swings, expected rainfall, and daily sunshine.
Bars span the average daily low to high. Jan is typically driest at 6 rainy days (29mm); Apr the wettest at 12 rainy days (97mm).
| Month | Average high | Average low | Daily sunshine | Rainy days | Total rainfall |
|---|---|---|---|---|---|
| Jan | -6°C / 21°F | -13°C / 8°F | 5h | 6 | 29mm |
| Feb | -4°C / 24°F | -13°C / 8°F | 7h | 7 | 32mm |
| Mar | 1°C / 33°F | -8°C / 18°F | 8h | 7 | 45mm |
| Apr | 6°C / 42°F | -2°C / 28°F | 8h | 12 | 97mm |
| May | 14°C / 57°F | 5°C / 40°F | 12h | 9 | 69mm |
| Jun | 19°C / 65°F | 10°C / 50°F | 12h | 11 | 97mm |
| Jul | 22°C / 71°F | 14°C / 57°F | 13h | 10 | 78mm |
| Aug | 22°C / 71°F | 14°C / 58°F | 11h | 9 | 47mm |
| Sep | 19°C / 66°F | 12°C / 53°F | 10h | 9 | 53mm |
| Oct | 12°C / 54°F | 6°C / 42°F | 7h | 10 | 70mm |
| Nov | 4°C / 39°F | -2°C / 28°F | 5h | 7 | 40mm |
| Dec | -2°C / 28°F | -9°C / 15°F | 4h | 11 | 49mm |
Weather data by Open-Meteo.com (opens in a new tab)
Frequently Asked Questions
When is the sunniest time of year to visit Thunder Bay?
July is the sunniest month in Thunder Bay, averaging 13 hours of sunshine a day. Pack a pair of sunglasses for clear days.
What clothes should I pack for Thunder Bay?
Your packing list depends entirely on when you travel. Temperatures in Thunder Bay swing from an average low of -13°C9°F in January up to 22°C72°F in August. The Packola app builds a tailored packing list for you based on the live weather forecast for your exact travel dates.
Do I need to pack an umbrella for Thunder Bay?
Thunder Bay gets rain on about 108 days a year, with April being the wettest. If you're traveling then, pack an umbrella and a light rain jacket.
Pack smarter.
Averages get you close, but the week you travel is what matters. Get the live forecast, a smart packing list, and discover the best local spots and activities in Thunder Bay with Packola.
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