A Chilly Start Leads to Sunny Skies and Comfortable Mid-June Temperatures
Friday: Cool, Crisp, and Clearing Up
Thunder Bay begins Friday, June 13, with a brisk start to the day. As of 6:00 AM EDT, the temperature is just 3.3°C at Thunder Bay Airport under mostly cloudy skies. The humidity is sitting at 100%, making the morning feel extra damp, though not quite foggy. Winds are light out of the west-southwest at 5 km/h, and visibility holds strong at 16 km. The pressure is rising at 102.6 kPa, setting the stage for improving weather through the day.
The forecast calls for mainly sunny skies once the early morning cloud clears, with a high of 15°C this afternoon. While that’s on the cooler side for mid-June, it’ll feel pleasant in the sun. The UV index is 8, which is very high, so be sure to throw on the sunscreen even if you’re bundled up — those rays are powerful this time of year.
Tonight: Frost Risk? In June? You Bet.
Tonight will be clear and cool, with the temperature dropping to just 3°C, and there is a risk of frost in some low-lying or sheltered areas. Yes, frost in mid-June. Welcome to Thunder Bay — where the only thing predictable is the unpredictability. Gardeners, take note: it might be a good idea to cover any sensitive plants, just in case Jack Frost decides to crash the party.
Saturday: Classic Northern Ontario Sunshine
Saturday offers a beautiful rebound with sunny skies all day and a slightly warmer high of 16°C. Still not scorching, but ideal for hikes, lakeside walks, and market mornings. The UV index will again reach 8, so sun protection remains a must.
Saturday night brings cloudy periods, with a low of 5°C — not quite frost territory, but still cool enough for a jacket or sweater.
Sunday: A Cloudier Close
Sunday will be cloudy but mild, with the high rising to 18°C — a slow and steady climb toward more seasonable conditions. Sunday night stays cloudy, with a low of 7°C, making for a much more comfortable overnight than Friday’s frosty flirtation.
What to Wear
Layers are key this weekend. Mornings will feel cold — especially today and Saturday — so a warm jacket or hoodie is essential. By midday, a light sweater or long sleeves should do the trick. And regardless of the temperature, don’t forget sunscreen — that UV index won’t take a break just because it’s chilly.
Historic Weather Trivia
On June 13, Thunder Bay has seen everything from chilly breezes to hot blasts. The record high for this date is a toasty 32.8°C, set in 1987, while the record low was a frosty -0.6°C way back in 1966. So, while today’s cool conditions and potential frost are unusual, they’re not unheard of — just one of the many moods of Lake Superior’s backyard.
