Thunder Bay – Weather – Northwestern Ontario is opening Monday with a cool, generally quiet morning before a more unsettled weather pattern arrives tonight and Tuesday. Kenora, Fort Frances, Red Lake, Vermilion Bay, Dryden, Sioux Lookout and Pickle Lake will all enjoy at least some sunshine today, with afternoon highs ranging from 22°C to 24°C.
The significant change comes tonight. A 60 percent chance of showers and a risk of thunderstorms develops across most of the region from Kenora through Sioux Lookout. Pickle Lake stays drier tonight, but showers move into that community Tuesday. Tuesday will be humid and unsettled, with Fort Frances potentially reaching a humidex near 33 and west winds gusting to 50 km/h.
Today’s Weather Overview
Kenora
Current Conditions
At 6:00 AM CDT, Kenora Airport was reporting partly cloudy skies and 11.9°C. Humidity was 85 percent, barometric pressure was 101.8 kPa and falling, and winds were from the south-southeast at 9 km/h. Visibility was 32 kilometres.
Monday begins with sunshine before clouds increase this morning. Southeast winds strengthen to 20 km/h gusting to 40, and the temperature climbs to 24°C, with a humidex of 26. The UV index will be 6, or high.
Tonight turns mainly cloudy with a 60 percent chance of showers and a risk of thunderstorms. South winds may gust to 40 km/h later in the evening. The overnight low is 16°C.
Fort Frances
Current Conditions
Fort Frances had a particularly chilly start. At 7:00 AM CDT, the temperature was just 5.0°C, with humidity at 97 percent. Pressure was 101.9 kPa and rising, while north-northwest winds were very light at 3 km/h. The station was not providing a sky-condition observation at that hour.
Sunshine gives way to a mix of sun and cloud this morning. The high reaches 23°C, with a humidex of 26 and a high UV index of 7.
Tonight becomes mainly cloudy with a 60 percent chance of showers and a risk of a thunderstorm. Southeast winds develop near morning at 20 km/h. The low will be 16°C.
Red Lake
Current Conditions
At 7:00 AM CDT, Red Lake Airport was reporting 9.7°C. Humidity was 90 percent, pressure was 101.9 kPa, and winds were calm. No sky condition was reported by the station at that observation.
Fog patches dissipate this morning, followed by sunshine and then a mix of sun and cloud this afternoon. South winds increase to 20 km/h, with a high of 22°C and a high UV index of 6.
Tonight becomes cloudy with a 60 percent chance of showers and a thunderstorm risk. South winds may gust to 40 km/h late tonight. The low is 15°C.
Vermilion Bay
Current Conditions
Environment Canada’s nearby Rawson Lake station was reporting 10.6°C at 6:00 AM CDT. Humidity was 85 percent, pressure was 101.8 kPa and rising, and south winds were light at 5 km/h. A sky condition was not reported.
Fog patches dissipate this morning before sunny skies give way to a mix of sun and cloud this afternoon. The high reaches 22°C, with a high UV index of 6.
Tonight brings mainly cloudy skies and a 60 percent chance of showers with a risk of thunderstorms. Southeast winds increase to 20 km/h gusting to 40 after midnight, with a low of 13°C.
Dryden
Current Conditions
At 6:00 AM CDT, Dryden Airport was clear and 11.3°C. Humidity was 86 percent, pressure was 101.9 kPa, and south winds were blowing at 9 km/h. Visibility was 16 kilometres.
Monday will be sunny before a mix of sun and cloud develops this afternoon. Morning fog patches dissipate, and the high reaches 22°C. The UV index will be 6, or high.
Clouds take over tonight with a 60 percent chance of showers and a thunderstorm risk. Southeast winds increase to 20 km/h gusting to 40 after midnight. The overnight low is 13°C.
Sioux Lookout
Current Conditions
Sioux Lookout had the coldest start in this roundup. At 6:00 AM CDT, the airport was reporting fog patches and just 4.4°C. Humidity was 100 percent, pressure was 102.0 kPa and steady, and north winds were barely moving at 2 km/h.
The fog dissipates this morning, leaving sunny skies and a high of 22°C. The UV index reaches 6, or high.
Tonight becomes mainly cloudy with a 60 percent chance of showers and a risk of a thunderstorm. West winds develop after midnight at 20 km/h gusting to 40, while the temperature drops to 14°C.
Pickle Lake
Current Conditions
At 7:00 AM EST, Pickle Lake Airport was reporting sunshine and 8.9°C. Humidity was 97 percent, pressure was 101.9 kPa, and southwest winds were blowing at 8 km/h.
Fog patches dissipate this morning, leaving a sunny Monday with a high of 22°C. The UV index reaches 6, or high.
Unlike communities farther west, Pickle Lake stays dry tonight. Expect partly cloudy skies and a low of 13°C.
Tomorrow’s Forecast
Tuesday, August 25 — Showers, Thunderstorms and Humidity
Tuesday is the most unsettled day of the immediate forecast.
Kenora will be cloudy with a 60 percent chance of showers and a thunderstorm risk. Southwest winds reach 20 km/h before easing late in the morning. The high is 23°C, but a humidex of 29 will make it feel warmer.
Fort Frances becomes the regional warm spot, reaching 26°C with a humidex of 33. There is a 60 percent chance of showers and a thunderstorm risk. Winds shift from southeast to west and strengthen to 30 km/h gusting to 50 late in the morning.
Red Lake will be cloudy with a 60 percent chance of showers and thunderstorms, south winds gusting to 40 km/h and a high of 21°C.
Vermilion Bay and Dryden both reach only 20°C, but humidity pushes the humidex to around 28. Both communities have a 60 percent chance of showers and a risk of thunderstorms, with south winds gusting to 40 km/h.
Sioux Lookout also reaches 20°C with a 60 percent chance of showers and thunderstorms. South winds increase to 30 km/h before easing later in the day.
Pickle Lake will see a 40 percent chance of morning showers before a few showers develop around noon. Thunderstorms are possible through the morning and afternoon, with 10 to 15 millimetres of rain possible. The high reaches 22°C with a humidex of 27.
Wednesday, August 26 — Still Unsettled
Wednesday remains cloudy or partly cloudy with scattered showers.
Kenora reaches 24°C with a 30 percent chance of showers. Fort Frances reaches 24°C, also with a 30 percent chance. Red Lake warms to 23°C under a mix of sun and cloud with a 30 percent shower risk.
Vermilion Bay and Dryden both reach 23°C with a 30 percent chance of showers. Sioux Lookout reaches 22°C with a similar 30 percent chance, while Pickle Lake remains cloudy with a 40 percent chance of showers and a high of 22°C.
Thursday, August 27 — Cooler Air Returns
Thursday brings a gradual improvement but also cooler temperatures, particularly toward Pickle Lake.
Kenora reaches 22°C, Fort Frances 23°C, Red Lake 20°C, Vermilion Bay and Dryden 21°C, and Sioux Lookout just 19°C. Each currently carries a 30 percent chance of showers.
Pickle Lake will be significantly cooler with a high of only 17°C and a 30 percent chance of showers.
Wardrobe Recommendations
Monday is a classic layering day. Temperatures are starting as low as 4°C in Sioux Lookout and 5°C in Fort Frances but will climb into the low to mid-20s by afternoon. A hoodie or light jacket will be useful early, while short sleeves should be comfortable later.
With UV levels reaching the high category across much of the region, sunscreen, sunglasses and a hat remain worthwhile even though clouds increase later.
Anyone out tonight or Tuesday should add a light waterproof jacket to the plan. Thunderstorms become possible across most communities, and winds will become gusty in several areas. Tuesday’s stronger winds around Fort Frances, Red Lake, Vermilion Bay and Dryden may also make a wind-resistant outer layer useful.
For boating and fishing, Monday daytime offers the better weather window in many locations. Conditions become less favourable tonight and Tuesday as showers, thunderstorms and stronger winds spread across the region.
Weather Trivia
Late August increasingly highlights the temperature difference between the southern and northern portions of Northwestern Ontario. Environment Canada’s August 24 normals put Kenora’s typical daytime maximum near 22°C, while Pickle Lake’s normal high is closer to 20°C. Their normal overnight lows are approximately 12°C and 10°C, respectively.
Monday’s forecast turns that pattern on its head slightly: both Pickle Lake and several communities farther south are expected to reach about 22°C, while Kenora climbs to 24°C. The much colder early-morning readings around Sioux Lookout and Fort Frances show how quickly inland locations can cool under favourable late-summer nighttime conditions.
Source: Environment and Climate Change Canada observations from approximately 6:00 to 7:00 AM and public forecasts issued at 4:30 AM on Monday, August 24, 2026. Forecast details can change quickly where thunderstorms are involved.
