Thunder Bay residents are stepping into a cool and cloudy Tuesday morning, with high humidity and a chance of showers and thunderstorms expected later in the day. While temperatures remain below seasonal norms today, a return to sunny skies and warmer conditions is on the horizon midweek.

Today’s Weather Overview

Current Conditions

As observed at 7:22 AM EDT at Thunder Bay Airport:

• Temperature: 13.6°C

• Condition: Mostly Cloudy

• Wind: Southeast at 6 km/h

• Pressure: 101.8 kPa and falling

• Dew Point: 12.8°C

• Humidity: 95% — quite damp

• Visibility: Excellent at 32 km

Today’s forecast calls for a mix of sun and cloud, but with a 60% chance of showers and the risk of a thunderstorm. The high will only reach 17°C, making it a cooler-than-average day for early July. Despite that, the UV index is 8, which is very high, so sun protection remains important during any clear breaks.

Tomorrow’s Forecast

Expected Conditions

Wednesday, July 9, 2025

• Daytime: A sunny and warmer day with temperatures rebounding.

  • High: 23°C

  • Humidex: 26

  • UV Index: 8 (Very High)

• Night: Clear skies and a comfortable low of 11°C.

Thursday, July 10, 2025

• Daytime: Another sunny day and ideal summer weather.

  • High: 23°C

• Night: Cloudy periods move in.

  • Low: 14°C

Friday, July 11, 2025

• Daytime: Skies become cloudy, but it remains mild.

  • High: 21°C

• Night: Cloudy with a 40% chance of showers.

  • Low: 14°C

Wardrobe Recommendations

• Today: Layer up for the cool and damp conditions. A light rain jacket and waterproof shoes are smart, especially if heading out in the afternoon. Don’t forget sunscreen during brighter moments.

• Wednesday–Thursday: Ideal weather for shorts, t-shirts, and sunglasses. With a high UV index, apply sunscreen liberally.

• Friday: Add a light windbreaker or sweater, with a rain jacket or umbrella ready for the evening hours.

Weather Trivia

Did you know?
Thunder Bay holds the record for the coldest July temperature in Ontario: 0.6°C, recorded on July 4, 1927. While today’s cooler conditions are nowhere near that extreme, they’re a reminder of the region’s capacity for significant summer variability.