Thunder Bay is starting Wednesday with a crisp, below-freezing morning, but the city is set for a pleasant warm-up through the day. After waking up to sunshine and a wind chill below zero, residents can expect spring to make a stronger appearance this afternoon with a high near 12°C. However, the break in the unsettled weather will be short-lived, as showers and even a risk of thunder return tonight and into Thursday.
Today’s Weather Overview
Current Conditions
At 7:00 AM EDT on Wednesday, April 22, 2026, Thunder Bay was reporting mainly sunny skies with a temperature of -2.0°C.
Other current conditions include:
- Pressure: 101.7 kPa and rising
- Humidity: 78%
- Dew point: -5.3°C
- Wind: WSW 8 km/h
- Wind chill: -5
- Visibility: 32 km
It is a cold start, but with rising pressure and bright skies, conditions are setting up for a much more comfortable afternoon.
Environment Canada’s forecast calls for a mix of sun and cloud becoming sunny this morning, with a daytime high of 12°C. The UV index is 6, or high, so even though the morning is chilly, the sun will have some strength by midday.
Tomorrow’s Forecast
Expected Conditions
Tonight
Tonight begins clear, but the weather turns more unsettled after midnight. Forecast details call for:
- Clear skies early
- Increasing cloudiness after midnight
- A few showers overnight
- Risk of a thunderstorm overnight
- Wind becoming northeast 20 km/h before morning
- Low: 3°C
Thursday, April 23
Thursday will bring more unsettled spring weather:
- A few showers ending in the morning
- Then a mix of sun and cloud
- Risk of a thunderstorm in the morning
- Wind east 30 km/h, becoming light in the morning, then increasing again late in the morning
- High: 8°C
- UV index: 6 or high
Thursday Night
- Cloudy
- 30% chance of showers
- Low: 4°C
Friday, April 24
Friday looks wetter and cooler:
- Periods of rain
- High: 6°C
Friday night continues damp, with:
- Periods of rain
- Low: 1°C
Looking a little farther ahead, Saturday brings a 40% chance of showers and a high of 6°C, while Saturday night could even see a 30% chance of flurries with a low of -2°C. Sunday looks better, with a mix of sun and cloud and a warmer high of 12°C.
Wardrobe Recommendations
This is a classic northwestern Ontario spring day where dressing in layers is the smart move.
For today:
- Start with a warm jacket this morning
- By afternoon, a lighter spring coat or sweater should be enough
- Because the UV index is high, sunglasses are a good idea
For tonight and Thursday:
- Keep a rain jacket or umbrella handy
- Waterproof footwear may be useful if showers develop overnight or during the Thursday morning commute
Weather Trivia
Did you know? In Thunder Bay, April is one of the most unpredictable weather months of the year. It is not unusual to start the morning below freezing, warm into the low double digits by afternoon, and then swing back to rain — or even flurries — within a day or two. That is one of the reasons spring in northwestern Ontario keeps everyone guessing.
Summary
Thunder Bay weather report for April 22, 2026: a cold sunny start gives way to a spring high of 12°C, followed by overnight showers and a risk of thunderstorms into Thursday.
