Northwestern Ontario weather for September 6-8, 2026: Warm Sunday temperatures give way to thunderstorms, strong winds and a wet Labour Day Monday
THUNDER BAY Weather Desk – WEATHER – Sunday, September 6, 2026 – Northwestern Ontario’s final days of the Labour Day weekend are turning increasingly unsettled, with warm and humid air Sunday giving way to thunderstorms, gusty winds and widespread showers.
Sunday will still feel like summer in many communities. Highs range from 22°C in Kenora and Pickle Lake to 27°C in Armstrong, with Dryden, Vermilion Bay, Ignace and Sioux Lookout reaching the mid-20s.
The change becomes more noticeable Sunday night and Labour Day Monday. Thunderstorms remain possible, winds could become strong around Kenora and Red Lake, and daytime temperatures fall sharply in northern communities.
Another system follows Monday night into Tuesday, bringing rain or a high probability of showers to essentially the entire region.
Today’s Weather Overview
Kenora
Sunday, September 6
Kenora will be cloudy with a 60 percent chance of showers late this afternoon and a risk of a thunderstorm.
Southeast winds develop near 20 km/h late in the afternoon.
The high reaches 22°C, with a humidex of 29 and a moderate UV index of 5.
Tonight becomes considerably more active. There is a 60 percent chance of showers and a thunderstorm risk, while southeast winds near 20 km/h shift southwest and strengthen dramatically to 50 km/h gusting to 70 km/h before easing later in the evening.
The low is 17°C.
Labour Day Monday, September 7
Monday remains cloudy with a 60 percent chance of showers and a risk of thunderstorms.
Southeast winds develop near 20 km/h in the afternoon. The high reaches 21°C, with a humidex of 27.
Rain becomes more persistent Monday night, with a low of 18°C.
Tuesday, September 8
Tuesday remains cloudy with a 60 percent chance of showers and a high of 23°C.
Tuesday night stays unsettled with another 60 percent shower chance and a low of 12°C.
Fort Frances
Sunday
Fort Frances will be mainly cloudy with a 60 percent chance of late-afternoon showers and a risk of thunderstorms.
Southeast winds develop at 20 km/h late in the afternoon.
The high reaches 24°C, but humidity pushes the humidex to 32.
Tonight remains mainly cloudy with a 60 percent shower chance and thunderstorm risk. Winds shift from southeast to west and may gust to 40 km/h before easing overnight.
The low is 17°C.
Labour Day Monday
Cloudy skies continue with a 60 percent chance of showers and a thunderstorm risk.
The high reaches 24°C, with a humidex of 31. Southeast winds develop near 20 km/h during the afternoon.
Rain follows Monday night with a mild low near 18°C.
Tuesday
Tuesday will be cloudy with a 60 percent chance of showers and a high of 25°C.
Tuesday night remains unsettled, with a 60 percent shower chance and a low of 14°C.
Vermilion Bay and Dryden
Sunday
Dryden and Vermilion Bay begin cloudy before becoming a mix of sun and cloud this morning.
A 60 percent chance of showers develops late this afternoon, along with a risk of thunderstorms.
The high reaches 25°C, with a humidex of 30 and a high UV index of 6.
Tonight remains cloudy with a 60 percent shower chance and thunderstorms possible. West winds increase to 30 km/h gusting to 50 km/h this evening before becoming light overnight.
The low is 17°C.
Labour Day Monday
Monday is cloudy with a 60 percent chance of showers and a risk of thunderstorms.
The high falls to 20°C, feeling closer to 25 with the humidex.
Rain is forecast Monday night, with a low of 17°C.
Tuesday
Tuesday remains cloudy with a 60 percent chance of showers and a high of 23°C.
The shower risk continues Tuesday night, with a low of 13°C.
Ignace
Sunday
Ignace begins mainly cloudy before clearing late this morning.
It will be warm, reaching 25°C, with a humidex of 31 and a high UV index of 6.
Cloud increases again early this evening, followed by a 60 percent chance of showers and a risk of thunderstorms. South winds develop near 20 km/h late tonight.
The overnight low is 16°C.
Labour Day Monday
Monday will be cloudy with a 60 percent chance of showers and thunderstorms.
The high reaches 22°C, with a humidex of 28.
Rain becomes more widespread Monday night, with temperatures near 17°C in the Dryden-Ignace forecast area.
Tuesday
Tuesday remains cloudy with a 60 percent chance of showers and a high near 23°C.
Tuesday night stays unsettled near 13°C.
Red Lake
Sunday
Red Lake gets a mix of sun and cloud, followed by a 60 percent chance of late-afternoon showers and a risk of a thunderstorm.
East winds increase to 20 km/h late this afternoon.
The high reaches 23°C, with a humidex of 28.
Sunday night could be particularly windy.
Environment Canada forecasts a 60 percent chance of showers and thunderstorms, with winds shifting from east to north before becoming southeast 50 km/h gusting to 70 km/h late this evening.
The low is 14°C.
Labour Day Monday
Monday remains cloudy with a 60 percent chance of showers and thunderstorms.
East winds increase to 30 km/h gusting to 50 km/h late in the morning.
The high reaches only 19°C.
Rain follows Monday night, with a low near 17°C.
Tuesday
Tuesday stays cloudy with a 60 percent chance of showers and a high of 22°C.
Tuesday night remains cloudy with a 60 percent shower chance and a low of 12°C.
Sioux Lookout
Sioux Lookout was reporting fog patches and 13.2°C at 5:00 a.m. CDT Sunday, with humidity at 100 percent, pressure at 102.0 kPa and light southeast winds.
Sunday
A mix of sun and cloud dominates much of the day, but the chance of showers rises to 60 percent late this afternoon, with a risk of thunderstorms.
The high reaches a warm 26°C, with a humidex of 31 and a high UV index of 6.
Tonight remains mainly cloudy with a 60 percent chance of showers and thunderstorms. Northwest winds develop near 30 km/h late this evening before easing overnight.
The low is 15°C.
Labour Day Monday
Monday turns cloudy with a 60 percent chance of showers and thunderstorms.
East winds increase to 20 km/h gusting to 40 km/h late in the afternoon.
The high falls to 19°C.
Rain follows Monday night with a low near 15°C.
Tuesday
Tuesday remains cloudy with a 60 percent chance of showers and a high of 23°C.
Tuesday night carries another 60 percent shower chance with a low of 13°C.
Armstrong
Sunday
Armstrong gets one of the warmest forecasts in Northwestern Ontario today.
Expect a mix of sun and cloud with a high of 27°C, a humidex of 29 and a high UV index of 6.
Tonight becomes mainly cloudy with a 60 percent chance of showers and a risk of thunderstorms.
The low is 14°C.
Labour Day Monday
A major temperature drop arrives Monday.
Expect cloudy skies, a 60 percent chance of showers and a risk of thunderstorms.
Southeast winds near 20 km/h become light late in the morning before east winds develop at 20 km/h gusting to 40 km/hduring the afternoon.
The high reaches just 17°C — ten degrees cooler than Sunday.
Monday night stays cloudy with a 60 percent chance of rain and a low of 13°C.
Tuesday
Tuesday turns wet with rain forecast and a high of 20°C.
Tuesday night remains cloudy with a 60 percent chance of showers and a low of 14°C.
Pickle Lake
Sunday
The latest Environment Canada Pickle Lake forecast calls for increasing cloud with an afternoon shower risk and possible thunderstorms.
The high is near 22°C, with humidex values into the upper 20s.
Sunday night becomes cloudy with a 60 percent chance of showers and a thunderstorm risk. Northeast winds develop near 20 km/h and the low falls to about 11°C.
Labour Day Monday
Monday turns markedly cooler.
Expect cloudy skies with a chance of rain and a high near 14°C.
Rain becomes more widespread Monday night, with a low near 12°C.
Tuesday
Tuesday remains wet, with rain or a high probability of rain and a high near 21°C.
Showers remain possible Tuesday night, with a low around 11°C.
Regional Three-Day Weather Trend
Sunday is the warmest day of this forecast for much of Northwestern Ontario.
Afternoon highs range from about 22°C in Kenora and Pickle Lake to 27°C in Armstrong, while Sioux Lookout reaches 26°C and Dryden, Vermilion Bay and Ignace reach 25°C.
The warmth comes with increasing instability. Thunderstorms become possible across much of the region during the afternoon or evening.
Sunday night is particularly important for wind. Kenora and Red Lake could see gusts reaching 70 km/h, while Dryden and Vermilion Bay could gust to 50 km/h.
Labour Day Monday is cooler and wetter, especially farther north and east. Armstrong falls from 27°C Sunday to 17°C Monday, while Pickle Lake drops into the mid-teens.
Tuesday brings another widespread round of precipitation, with rain forecast around Armstrong and Pickle Lake and 60 percent shower probabilities across Kenora, Fort Frances, Dryden, Red Lake and Sioux Lookout.
Highway and Travel Outlook
Anyone travelling home from the Labour Day weekend should be prepared for changing road conditions.
Thunderstorms and heavy showers could briefly reduce visibility Sunday evening along Highways 17, 71, 72, 105 and 599.
Strong wind gusts may also affect exposed highway sections around Kenora, Dryden and Red Lake Sunday night.
Monday will be a wetter travel day across much of the region, while persistent rain Monday night into Tuesday could lead to areas of ponding on roads.
Drivers should monitor updated forecasts and radar before longer trips.
Boating and Outdoor Outlook
Sunday morning and early afternoon provide the better outdoor window in many communities, but conditions become increasingly unpredictable later in the day.
Boaters on Lake of the Woods, Rainy Lake, Wabigoon Lake, Lac Seul and Red Lake should be prepared to head for shore quickly if thunderstorms develop.
The combination of thunderstorms and potentially strong wind shifts Sunday evening makes open-water travel less favourable later in the day.
Labour Day Monday and Tuesday are generally poorer choices for extended boating trips because of widespread showers or rain.
Wardrobe Recommendations
Sunday still supports summer clothing during the afternoon, especially across Dryden, Ignace, Sioux Lookout and Armstrong.
Keep a waterproof jacket close by, however, as showers and thunderstorms develop.
Monday requires more layering, particularly around Red Lake, Sioux Lookout, Armstrong and Pickle Lake, where temperatures fall sharply.
A wind-resistant outer layer will also be useful around Red Lake and Armstrong.
By Tuesday, rain gear and waterproof footwear will be practical across much of Northwestern Ontario.
Weather Trivia
Sunday’s forecast highlights how dramatic September temperature swings can be in Northwestern Ontario.
Armstrong is forecast to reach 27°C Sunday, compared with a seasonal normal high near 17°C. By Labour Day Monday, the forecast high falls to just 17°C, returning the community almost exactly to normal in roughly 24 hours.
Kenora’s normal high is about 18°C, so even its rainy Tuesday forecast of 23°C remains well above normal for early September.
Source: Environment and Climate Change Canada Northern Ontario public and extended forecasts issued at 5:30 a.m. EDT Sunday, September 6, 2026, along with current Environment Canada community forecasts.
Summary
Northwestern Ontario weather for September 6-8, 2026: Warm Sunday temperatures give way to thunderstorms, strong winds and a wet Labour Day Monday, with rain and showers continuing Tuesday across Kenora, Fort Frances, Dryden, Red Lake, Sioux Lookout, Armstrong and Pickle Lake.
