September 23, 2025: Toronto’s Detailed Weather Forecast

TORONTO – WEATHER – Heading to Toronto for business, pleasure, or a medical appointment? Be sure to pack an umbrella and dress for humidity. After a muggy start to the day, a system moving through southern Ontario brings showers and the risk of thunderstorms, continuing into Wednesday and Thursday. But drier and brighter skies are expected to return just in time for the weekend.

Today’s Weather Overview

Current Conditions

As of 7:00 AM EDT at Toronto Pearson International Airport, the skies are partly cloudy, with a temperature of 18.4°C and a dew point of 17.3°C. That means humidity is at 93%, and it feels quite muggy this morning.

Winds are light from the south at 6 km/h, and visibility is 19 km, though light fog or mist could be present in some areas.
Barometric pressure is steady at 101.3 kPa, indicating stable but humid air ahead of a disturbance this afternoon.

Forecast for Tuesday:

• Cloudy skies building through the morning.

• 40% chance of showers this afternoon.

• Risk of a thunderstorm late in the day.

• High of 23°C, with a humidex of 28°C—feeling quite summer-like.

• UV index 4 (moderate).

Tonight:

• Mainly cloudy with a 40% chance of showers.

• Risk of a thunderstorm early this evening.

• Low of 17°C.

Tomorrow’s Forecast

Expected Conditions

• Wednesday, September 24:

  • Cloudy with a 60% chance of showers.

  • Risk of a thunderstorm in the afternoon.

  • High of 21°C, with a humidex of 26°C.

  • UV index 5 (moderate).

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

  • Low of 15°C.

• Thursday, September 25:

  • Showers expected, with a daytime high of 22°C.

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

  • Low around 14°C.

• Friday, September 26:

  • A mix of sun and cloud, with a 30% chance of showers.

  • High near 23°C.

  • Night: Cloudy periods and a mild low of 14°C.

Wardrobe Recommendations

With muggy air and shifting skies, dress in layers and be ready for rain:

• Today & Wednesday:

  • Opt for breathable clothing—temperatures will feel warmer than they are.

  • Keep a small umbrella or compact rain jacket on hand for pop-up showers or storms.

  • Footwear: Waterproof shoes are a smart choice if you’re walking downtown.

• Thursday:

  • With showers expected, lean into weather-resistant outerwear.

• Friday:

  • Layer up in case of morning drizzle, but plan for lighter clothing as temperatures remain mild.

Weather Trivia

Did you know?
Toronto often sees some of its most humid days in September, especially when southerly winds bring moisture from the Great Lakes and U.S. Midwest. These “second summer” periods, like this week, are marked by warm humidex values, frequent cloud cover, and pop-up thunderstorms—not unlike the patterns we see in July!

Whether you’re walking downtown, attending a conference, or heading to a clinic — keep your umbrella close and check back with the NetNewsLedger Weather Desk for updates as conditions evolve!