Thunder Bay – Weather – Thursday is the day! Looking forward to the weekend it is going to be unsettled with precipitation and the potential for thunderstorms.

For today, Thursday, it’s a cool and cloudy morning in Thunder Bay, but conditions will turn sunny and pleasant as the day progresses. After today’s refreshing break, heat and humidity surge back Friday, bringing a risk of thunderstorms, followed by an unsettled weekend.

Today’s Weather Overview

Current Conditions (7:00 AM EDT – Thunder Bay Airport)

• Temperature: 9.1°C

• Condition: Mostly Cloudy

• Wind: West at 5 km/h

• Dew Point: 9.0°C

• Humidity: 99%

• Pressure: 101.6 kPa and falling

• Visibility: 32 km

After a chilly start and some morning cloud cover, skies will turn sunny by midday. Temperatures will rise to a high of 22°C, with a humidex of 25 — a comfortable and manageable summer day. The UV index is 8, meaning sun protection is important despite the cool morning air.

Tonight’s Forecast

• 🌙 Clear skies

• 🌡️ Low: 15°C — a warmer night ahead

Tomorrow’s Forecast – Friday, July 11

• 🌤️ Mix of sun and cloud, with a 30% chance of afternoon showers and risk of a thunderstorm

• 🌡️ High: 27°C

• 💧 Humidex: 34 — hot and muggy

• 🌞 UV Index: 8 (Very High)

• 🌙 Night: Showers expected | Low: 15°C

Weekend Outlook

Saturday, July 12

• 🌤️ Mix of sun and cloud, 60% chance of showers

  • High: 25°C

• 🌙 Cloudy periods with 30% chance of showers

  • Low: 13°C

Sunday, July 13

• 🌤️ Another partly sunny day, 30% chance of showers

  • High: 28°C

• 🌙 Cloudy periods with a chance of showers

  • Low: 16°C

Wardrobe & Activity Tips

• Today: Dress in layers. Morning jacket needed early, switching to short sleeves by afternoon. Apply sunscreen even with cooler temperatures — the UV index is very high.

• Friday: Prepare for summer heat — loose, breathable clothing and plenty of hydration are key. Storms could develop in the afternoon.

• Weekend: Have a light rain jacket ready. There will be dry breaks, but shower risks continue both Saturday and Sunday.

Weather Trivia

Did you know?
Thunder Bay’s cooler mornings are thanks to Lake Superior’s powerful moderating effect. But once that morning cloud burns off, the city can heat up quickly — as will be the case heading into Friday’s humidex of 34.