Sunny and warm today, but showers and thunderstorms may arrive by tonight as a late-summer surge continues

TORONTO – WEATHER – Whether you’re visiting Toronto for business or pleasure, the city is offering up classic September weather—mild mornings, warm and humid afternoons, and a few unsettled patches on the horizon.

After a mainly sunny and calm start to Sunday, a storm system will move in tonight, bringing a chance of showers and thunderstorms into Monday before more stable weather returns midweek.

Today’s Weather Overview

Current Conditions

As of 8:00 AM EDT at Toronto Pearson International Airport, skies are mainly sunny with a temperature of 13.5°C. The dew point is 9.6°C, with humidity at 77%, making for a comfortable and crisp early morning.

Winds are light from the northeast at 5 km/h, and visibility is excellent at 24 km. Barometric pressure is at 102.1 kPa and falling, signalling an approaching frontal system later in the day.

Forecast for Today:

• Mainly sunny through the morning and early afternoon.

• Winds shifting southeast at 20 km/h near noon.

• High of 25°C, with a humidex of 29—feeling almost summery.

• UV index 6 (high)—sun protection is a must.

Tonight:

• Clouds roll in this evening.

• 60% chance of showers and a risk of a thunderstorm late in the evening and overnight.

• Mild overnight low of 18°C.

Monday’s Forecast

Expected Conditions

• Monday, September 22:

  • Cloudy with a 60% chance of showers.

  • Risk of thunderstorms late in the afternoon.

  • Winds becoming southwest at 20 km/h, gusting up to 40 km/h by midday.

  • High of 25°C, with a humidex of 30—quite warm for late September.

  • UV index: 4 (moderate).

• Monday Night:

  • Cloudy periods, but rain chances taper off.

  • Low of 17°C.

• Tuesday, September 23:

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

  • Slightly cooler but still pleasant with a high of 23°C.

  • Night: Cloudy periods, low of 13°C.

• Wednesday, September 24:

  • Sunny skies return, with a refreshing high of 20°C.

  • Night: A cool, partly cloudy night with a low of 10°C.

Wardrobe Recommendations

Toronto’s weather this week requires layered planning and rain-ready gear for early-week outings:

• Sunday–Monday Daytime:

  • Light, breathable clothing is ideal due to warm and humid conditions.

  • A hat and sunscreen are recommended for today.

• Sunday Night–Monday Evening:

  • Bring an umbrella or waterproof jacket in case of showers or an isolated thunderstorm.

• Tuesday–Wednesday:

  • As temperatures dip slightly, light jackets or long sleeves will be more comfortable.

  • A sweater or scarf may come in handy for early mornings and evenings.

Weather Trivia

Did you know?
Toronto’s record high for September 21st is 31.1°C, set in 1947. While we won’t break records today, the city is still experiencing above-average temperatures for late September. Thanks to Lake Ontario’s warmth and southerly winds, humidex values near 30°C are not uncommon during this stretch of the month—an unofficial “second summer” before autumn cools things off more consistently.

If you’re heading out in Toronto today, enjoy the sunshine while it lasts, and stay weather-aware tonight and tomorrow. Check back with the NetNewsLedger Weather Desk for continued coverage throughout the week.