Thunder Bay – Weather – Thunder Bay is starting Tuesday under mostly cloudy skies and mild conditions, but today’s forecast brings a mix of local smoke, breezy winds, and the possibility of afternoon showers or thunderstorms. Temperatures will rise into the mid-20s, making it feel like late summer, but unsettled skies will dominate.

Today’s Weather Overview

Current Conditions (8:00 AM EDT – Thunder Bay Airport)

• Temperature: 16.3°C

• Humidity: 96%

• Dew Point: 15.7°C

• Wind: WNW 4 km/h

• Pressure: 100.7 kPa

• Visibility: 15 km

• Sky: Mostly cloudy

Daytime Forecast

• Conditions: Mainly cloudy with a 40% chance of showers and a risk of thunderstorms this afternoon. Local smoke may reduce visibility.

• Wind: Becoming west 20 km/h, gusting to 40 km/h this morning.

• High: 24°C

• Humidex: 29 (slightly muggy feel)

• UV Index: 6 – High

Tonight

• Conditions: Partly cloudy with a 30% chance of showers. Local smoke early this evening.

• Wind: NW 20 km/h becoming light.

• Low: 14°C

Tomorrow’s Forecast – Wednesday, August 13, 2025

• Daytime: Mainly cloudy.

• High: 23°C | Humidex: 26 | UV Index: 6 – High

• Night: Cloudy periods. Low 9°C.

Thursday, August 14, 2025

• Daytime: Cloudy with 30% chance of showers. High 19°C.

• Night: Cloudy with 30% chance of showers. Low 14°C.

Wardrobe Recommendations

• Today: Light layers for the mild start, adding a light jacket in case of showers. Sunglasses if sun breaks through, but also consider a mask if local smoke thickens.

• Tonight: A light sweater or hoodie for the cooler evening.

• Wednesday: Comfortable clothing with a light outer layer for cloudier, slightly humid conditions.

Weather Trivia

Smoke events in Thunder Bay are often linked to forest fires in northwestern Ontario or Manitoba. In August 2018, local smoke from regional fires reduced visibility to just 5 km in the city for several days — today’s smoke risk is less severe but still noticeable.