It's going to be a cooler than normal start to summer in southwestern Ontario.
The summer season officially started on Sunday, June 21, at 4:24 a.m.
Environment Canada Warning Preparedness Meteorologist Peter Kimbell said since the middle of June, it has been on the cooler side.
"And that trend is going to continue for the next little while," said Kimbell. "So if you asked me for the next day of 30 degree temperatures, probably not until the end of the month. And between now and then, it's going to remain cool like we've seen the last few days with highs around 21 degrees."
The average daytime high for the region this time of year is around 26 Celsius. Kimbell said we can expect daytime highs in the low 20s to continue until just before Canada Day.
"Whenever we have warm temperatures, like a heat wave, we have a big ridge of high pressure and we're seeing the opposite of that right now," said Kimbell. "We're seeing a big trough of low pressure kind of hanging over Ontario, and plaguing us with cooler than average temperatures. That's going to continue until the end of the month, we might get a bit warmth by the last couple days of June."
In its summer seasonal outlook, the national weather agency said a transition to El Niño is expected to develop this summer, taking full effect later this year.
"El Niño occurs when the surface water temperatures in the eastern tropical Pacific Ocean become warmer than average," read the outlook. "This rise in temperature changes the atmosphere circulation and weather patterns around the globe, which can impact food supplies, energy systems, and influence extreme climate, such as wildfire risk and a change in air-quality conditions."
Summer is also considered severe thunderstorm season.
Environment Canada encourages residents to regularly monitor weather forecasts, the AQUI and UV Index and to take all weather alerts seriously.
