Summer Steam and Shower Threats as Toronto Turns Up the Thermostat

Tuesday, June 17 – Warm, Muggy, and Mostly Pleasant… For Now

Toronto is waking up under partly cloudy skies with a balmy temperature of 16.3°C at Pearson International Airport. It’s a humid start with 91% humidity, and a southerly breeze at 7 km/h gently stirring the morning air. The barometer is sitting at 101.4 kPa and falling, signaling some instability on the horizon. Visibility is 16 km, with light haze hanging around the skyline.

As the morning unfolds, expect a mix of sun and cloud with temperatures soaring to 26°C — but don’t be fooled. With a humidex of 32, it’s going to feel like the inside of a greenhouse. The UV index is a blazing 9, so sunscreen isn’t optional unless you’re going for the “lobster” look.

Tonight – Warm and Watchful

Overnight, we’ll see partly cloudy skies, and a 30% chance of showers may interrupt your late-night patio chats. It’ll be warm and muggy, with a low of 19°C, making it one of those toss-and-turn evenings if you’re not a fan of AC.

Wednesday, June 18 – Sweltering and Stormy?

Hold onto your iced coffees! Wednesday brings another scorcher with a high of 29°C and a humidex that will make it feel more like 37°C. A mix of sun and cloud will dominate the skies, but by the afternoon, there’s a 40% chance of showers and the risk of a thunderstorm. It’s a classic summer flip — hot and sunny, then rumbling skies before dinner.

By nightfall, it turns cloudy with a 60% chance of showers, and temperatures ease down to 18°C.

Looking Ahead – Rainy Thursday, Sunny Friday

Thursday keeps the umbrellas in demand with a 60% chance of showers and a slightly cooler high of 25°C. Fortunately, things brighten just in time for the weekend. Friday is shaping up to be sunny and seasonal with a high of 24°C, perfect for those chasing a beach day or outdoor plans. Skies will be clear Friday night, with a low of 15°C.

Wardrobe Forecast

Dress light, breathable, and sweat-resistant today. It’s going to feel like a steam room by mid-afternoon. Sunglasses and sunscreen are essential, and an umbrella might come in handy tonight — just in case. A wide-brimmed hat won’t hurt either. Tomorrow, keep rain gear nearby and drink plenty of water — that humidex is no joke.

Weather Trivia – Toronto’s Humidex History

Did you know? The highest recorded humidex in Toronto was a stifling 53 back in 2011. While we’re not hitting that today, anything over 30 can make outdoor activity challenging — especially in a concrete jungle where heat sticks around longer.