Sunshine and a Few Showers Ahead!

Thunder Bay – Weather – Thunder Bay is having quite the mixed weather bag this week! Today, you’ll enjoy sunny skies with a high of 27°C, though be prepared for a 40% chance of showers by late afternoon, with possible thunderstorms sneaking in as well. Winds from the south at 20 km/h will add a bit of breeze to the day.

The humidex makes it feel closer to 33°C, so it’s definitely warm! Tonight will be cooler at 15°C, but with a higher 60% chance of showers and lingering thunderstorms—so you might want to keep your umbrella handy into the evening.

Looking forward, Wednesday will bring more sunshine with a high of 26°C, and clear skies overnight with a low of 13°C. On Thursday, the sun sticks around but temperatures dip slightly to 23°C before more clouds roll in at night. By Friday and into the weekend, showers are back on the agenda, with a 40% chance of rain on Friday and highs around 21°C, dropping to 18°C on Sunday.

Thunder Bay and Lake Superior West Marine Forecast

For those navigating Western Lake Superior, here’s the latest marine forecast:

• Today (Wednesday): Winds are expected to come from the southeast at 15 knots, gradually diminishing to lighter winds by the afternoon.
• Thursday: Winds will stay consistent at southeast 15 knots.
• Friday: Winds will pick up slightly, starting at southeast 15 knots and increasing to southeast 20 knots by the end of the day.

Conditions remain relatively calm, but as the week progresses, expect slightly stronger winds by Friday. No warnings are currently in effect, making it a relatively smooth few days ahead on the water​.

For those planning recreational or professional trips across the lake, these wind conditions suggest manageable sailing with potential for increased waves later in the week. Stay updated on further changes, as weather in the Great Lakes can shift quickly!

The seasonal average for this time of year in Thunder Bay is a high of 17°C and a low of 5°C, so you’re getting a nice warm stretch compared to the usual.

Wardrobe Tip: Light summer clothes for today and tomorrow, but keep a raincoat ready for the evenings and weekend. Sunglasses will still be handy during the day.

Trivia: Thunder Bay holds some of Ontario’s most dramatic swings between humid summers and cold winters—enjoy this late-season warmth while it lasts!