Labour Day Weekend 2026: Thunder Bay Forecast — Saturday Shines, Sunday Stays Warm, Showers Return Monday
THUNDER BAY – WEATHER – Friday, September 4, 2026 – Thunder Bay’s Labour Day long weekend will offer a little of everything: a cloudy and damp start Friday, a beautiful late-summer Saturday, continued warmth with a few showers possible Sunday, and a cooler, cloudier Labour Day Monday.
For people planning camping, hiking, fairs or other outdoor activities, Saturday currently offers the best weather window. Sunday remains warm enough for outdoor plans, including the opening day of the Hymers Fall Fair, but keeping rain gear nearby will be sensible. Monday becomes cooler with a greater chance of showers.
Today’s Weather Overview
Current Conditions
At 5:00 a.m. EDT Friday, Thunder Bay Airport was reporting mostly cloudy skies and 14.4°C.
Humidity was 100 percent, with a dew point of 14.4°C. Barometric pressure was 101.5 kPa and falling.
Winds were very light from the northwest at 3 km/h, and visibility was 24 kilometres.
Friday, September 4 — Cloudy Start to the Weekend
Friday will be cloudy with a 30 percent chance of showers.
Morning fog patches will dissipate, while east winds increase to 20 km/h.
The afternoon high reaches 21°C, with a humidex of 26. The UV index is 5, or moderate.
Friday night remains cloudy. East winds near 20 km/h become light late in the evening, with an overnight low of 14°C.
Friday Activity Ideas
Friday’s cloud and occasional shower risk favour activities where you can easily move indoors if necessary.
A waterfront walk at Marina Park and Prince Arthur’s Landing remains an option between showers. Temperatures in the low 20s should be comfortable for walking, although an umbrella or lightweight rain shell is worthwhile.
Saturday, September 5 — Best Outdoor Day
Saturday shapes up as the highlight of the weekend.
Expect a mix of sun and cloud, with the temperature climbing to 24°C.
The humidex reaches 28, while the UV index rises to 7, or high.
Saturday night will be clear and cool, falling to 9°C.
That combination of warmth, sunshine and a clear evening makes Saturday the strongest day for outdoor recreation.
Saturday Activity Ideas
Saturday is an excellent day for:
- A walk, picnic or bike ride at Marina Park
- Hiking around the Thunder Bay area
- A day trip toward Kakabeka Falls
- Fishing or paddling on sheltered inland waters, after checking the latest wind forecast
- An afternoon barbecue or backyard gathering
- Taking in the waterfront and views toward the Sleeping Giant
With the UV index reaching 7, sunscreen, sunglasses and a hat should be part of Saturday’s outdoor plans.
Sunday, September 6 — Warm with a Shower Risk
Sunday remains quite warm.
Environment Canada forecasts a mix of sun and cloud with a 30 percent chance of showers.
The high reaches 24°C.
Sunday night brings cloudy periods with a 40 percent chance of showers and a low near 11°C.
The relatively low daytime shower probability means outdoor activities remain reasonable, but conditions could vary considerably across the Thunder Bay district.
Hymers Fall Fair Opens Sunday
One of Northwestern Ontario’s traditional Labour Day weekend events returns Sunday.
The 2026 Hymers Fall Fair runs Sunday, September 6 from 9 a.m. to 6 p.m. and continues Monday.
This year’s theme is “Sunshine and Sunflowers.” The fair includes livestock and horse shows, agricultural exhibits, vendors, food, children’s activities, competitions and live entertainment on two stages.
Sunday’s forecast high of 24°C should make for comfortable fair weather, although the 30 percent shower chance means visitors should consider packing a light waterproof jacket.
The Sunday Main Stage lineup includes the Pipes and Drums of Thunder Bay, Southern Comfort, Pat Silvaggio, Gibson, Martin, and I, and Radar and the Rockets.
Taste of Fort William — Sunday
Thunder Bay’s official events calendar also lists Taste of Fort William from 11 a.m. to 4 p.m. Sunday at Fort William Historical Park.
The event explores multicultural fur-trade-era foods, historical cooking methods and contemporary Thunder Bay foods.
With a shower possible Sunday, this provides another good long-weekend outing where visitors can mix outdoor exploration with historical programming.
Family Art Day — Sunday
Families looking for an indoor or weather-flexible option can consider Family Art Days at the Thunder Bay Art Gallery from 1 p.m. to 4 p.m. Sunday.
The free, all-ages event includes creative activities and opportunities to explore gallery exhibitions.
This could be particularly useful if one of Sunday’s scattered showers develops during the afternoon.
Labour Day Monday, September 7 — Cooler and More Unsettled
Labour Day itself turns cooler.
Environment Canada is forecasting cloudy skies with a 40 percent chance of showers and a high of 20°C.
Monday night remains cloudy with a low of 14°C.
The temperature will be much closer to Thunder Bay’s seasonal normal high of about 20°C.
Hymers Fall Fair Continues Monday
The Hymers Fall Fair continues Labour Day Monday from 9 a.m. to 5 p.m.
Monday’s Main Stage entertainment includes Jim ’n’ I, TBay Trad, Pat Silvaggio, Flipper Flanagan Flat Footed Four and Tommy Milestone Horricks.
With temperatures near 20°C and a 40 percent shower chance, Monday visitors should dress in layers and carry rain gear.
The fairgrounds can also become muddy if showers pass through, making sturdy footwear a better choice than sandals.
Other Labour Day Activities
If the weather cooperates Monday afternoon or evening, a waterfront walk remains an easy option.
The Dawson Diner Monday Night Cruise-In from 6:30 p.m. to 8 p.m., weather permitting, featuring antique and classic vehicles.
Because Monday carries a 40 percent shower risk, people interested in the cruise-in should confirm the event is proceeding before heading out.
Long Weekend Outdoor Planning
Best overall outdoor day: Saturday.
Best fair day from a weather standpoint: Sunday currently looks warmer, although both Sunday and Monday carry shower risks.
Best waterfront day: Saturday, with 24°C and a mix of sun and cloud.
Best day for hiking: Saturday. Sunday is also workable, but monitor radar.
Wettest risk: Labour Day Monday, with a 40 percent chance of showers.
People camping for the weekend should prepare for a fairly significant temperature swing. Saturday reaches 24°C but falls to only 9°C overnight, so a warm sleeping bag and extra layers will be important.
Wardrobe Recommendations
Friday calls for a light rain jacket and comfortable layers.
Saturday is summer weather: shorts and T-shirts will be comfortable during the afternoon, but sunscreen is important with the UV index reaching the high category. Pack a sweater or fleece if staying outdoors Saturday evening because temperatures drop sharply after sunset.
Sunday remains warm enough for light clothing, but bring a waterproof shell for the shower risk.
For Labour Day Monday, jeans or longer pants, a light sweater and rain jacket will be more comfortable as temperatures settle near 20°C.
Weather Trivia
Thunder Bay’s seasonal normal maximum for early September is approximately 20°C, with a normal minimum near 7°C.
Saturday and Sunday’s forecast highs of 24°C are therefore about four degrees warmer than normal. Saturday night’s low of 9°C, however, provides a reminder that September nights are getting longer and cooler.
Sunrise Friday is at 7:18 a.m. EDT, with sunset at 8:33 p.m. EDT, leaving more than 13 hours of daylight for long-weekend activities.
Weather Source: Environment and Climate Change Canada Thunder Bay forecast issued at 5:30 a.m. EDT Friday, September 4, 2026. Event information is from the City of Thunder Bay/Visit Thunder Bay events calendar and the official Hymers Fall Fair schedule.
Overview
Thunder Bay Labour Day weekend weather for September 4-7, 2026: Cloudy Friday gives way to a warm 24°C Saturday, with shower chances Sunday and Labour Day Monday. Plus Hymers Fall Fair, Taste of Fort William, Family Art Days and other weekend activities.
