THUNDER BAY – Weather – You will need mittens for your kittens this morning! Thunder Bay is waking up to a cold Monday morning, with temperatures sitting at -10°C and a wind chill closer to -15. It is a frosty start to the week, but there is a spring rebound on the way. Sunshine and milder air return Tuesday, with daytime temperatures climbing into the double digits.
Today’s Weather Overview
Current Conditions
As of 6:00 AM EDT Monday, April 20, 2026, Thunder Bay was reporting partly cloudy skies with a temperature of -10.0°C.
The wind chill is making it feel like -15, while a light northwest wind at 9 km/h adds a cold edge to the morning. Humidity is 78%, the dew point is -13.1°C, and visibility is 24 km.
Barometric pressure is 102.6 kPa and rising, pointing to stable conditions early today.
Today’s Forecast
Thunder Bay will begin the day with sunshine before clouds increase near noon. Winds will become south at 20 km/h, gusting to 40 km/h this morning.
The high today will reach +5°C, but the morning will feel much colder, with a wind chill near -22. The UV index is 5, or moderate.
Tonight’s Forecast
Clouds will clear this evening, and winds from the southwest at 20 km/h will become light.
The overnight low will fall to -3°C, with a wind chill near -7 overnight.
Tuesday Outlook
Spring pokes her head out on Tuesday, bringing sunshine and a high of 14°C. Winds will be light, up to 15 km/h, though the morning will still feel chilly with a wind chill near -6.
Tuesday night will be clear, with a low of -2°C.
Midweek Forecast
Wednesday brings a mix of sun and cloud with a high of 13°C. Wednesday night turns unsettled, with cloudy skies and a 60 percent chance of showers. The low will be +4°C.
Thursday stays cloudy and mild with a 40 percent chance of showers and a high near 10°C. Rain chances continue Thursday night, with a 60 percent chance of showers and a low of 7°C.
By Friday, the forecast cools again, with a high near 9°C, a 40 percent chance of showers, and a 30 percent chance of flurries Friday night as temperatures drop to -2°C.
Weather Alerts and Hazards
The main issue this morning is the cold. Wind chills near -22 early today mean winter gear is still needed, especially for students heading to school, commuters, and anyone working outdoors.
Wardrobe Recommendations
Start the day with a winter coat, gloves, and a toque. It may be April 20, but the morning air is not playing nice.
By this afternoon, lighter layers will work better as temperatures rise above freezing. Tuesday will feel much more like spring, but the morning will still be cool enough for a jacket.
Weather Trivia
Thunder Bay’s spring weather often behaves like it cannot decide which season it belongs to. Late April can bring frosty mornings, wind chills below -20, and then sunshine with double-digit highs within 24 hours. This week is a perfect example: a freezer-style Monday morning followed by a much milder Tuesday.
