June can bring major heat waves, potent storms to Canada
From stuffy heat to heavy storms, the beginning of summer is typically an eventful adventure across Canada
Welcome to the beginning of summer, Canada! The start of June heralds the arrival of meteorological summer—with the summer solstice just a few short weeks away.
What does a typical June have in store across the country?
Severe thunderstorms are a common sight as the atmosphere warms up and an active jet stream lifts across our side of the border. Building heat can make for spells of sweltering conditions from coast to coast—sometimes to surprising extremes.
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Major heat can build in June
Meteorologists consider June 1 the start of the summer season because the atmosphere is primed for classic heat, humidity, and storms well before the sun reaches its highest point in the sky.
Even though June sometimes features cold, frost, and even some snow for communities up north, the last gasps of the cold season are behind us for most of Canada’s population centres.
Snow can still lurk from time to time, though. Measurable snow fell across St. John’s, N.L., back in June 2021—and accumulating snow isn’t unprecedented in Newfoundland or out west in the Rockies throughout the month. Calgary saw 24.9 cm of snow on June 6, 1951.
Daily average temperatures gradually rise through an average June as summertime heat settles across the country.
Typical daytime highs through the month hover between 24°C and 25°C in Toronto, Ottawa, and Montreal. A normal daytime reading comes in around the upper teens to the 20-degree mark in Vancouver, Calgary, Edmonton, and Halifax.
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The 30-degree temperatures that popped up across Canada in May are a more frequent sight during the month of June. It’s not uncommon to see genuine heat waves this time of year.
The hottest June day on record in Toronto came in at 36.7°C back on June 25, 1952, while Winnipeg’s hottest-ever June day saw a high of 37.8°C on June 17, 1995. Abbotsford, B.C., climbed to an astounding 42.9°C during the awful heat dome event in late-June 2021.
Precipitation begins to peak as humidity arrives
It’s not just the heat building across the country—humidity begins to spill north of the border right along with it.
Excess moisture in the atmosphere can make a June afternoon start to feel sticky or even dangerous to our health. But it can also fuel some pretty serious downpours, especially when a potent thunderstorm bubbles up.
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June is historically the wettest month of the year for a wide swath of the Prairies, as well as Toronto. Folks in Calgary average around 112.7 mm of precipitation during a normal June, while the month usually brings Toronto around 80 mm of precipitation.
Heavy rain isn’t the only threat in June’s potent thunderstorms. Frequent rounds of severe weather can produce damaging wind gusts, large hail, and tornadoes.
Sunlight reaches its seasonal peak
The arrival of the summer solstice—which falls on June 20 this year—marks the Sun’s highest point in the sky, providing Canada our longest days of the year.
Ottawa averages around 15 hours and 40 minutes of daylight around the summer solstice, while Vancouver is in line for about 16 hours and 14 minutes of daylight over the same time period.
Nunavut’s capital of Iqaluit, situated near the Arctic Circle, will experience just under 21 hours of daylight near the solstice. Inuvik, which is north of the Arctic Circle, saw the sun rise on May 23—and it won’t set there again until July 18 this year.
But how much of that sunlight will the weather actually allow residents to enjoy? Toronto averages about 9.9 hours of sunshine on a typical June day. Fewer clouds over Edmonton increases their average daily sunshine to 11.1 hours.