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Southern Ontario faces summery Sunday with another risk of storms
Warm and humid air could fuel multiple chances for storms across southern Ontario through the end of the weekend
A taste of tropical air pushing into Ontario to end the weekend will provide an early taste of summer for much of the region.
The arrival of warmth and humidity may fuel opportunities for thunderstorms again during the day Sunday.
Warmth will linger into the beginning of the work week, but with dramatic temperature changes as the cooler lakes flex their influence over the shorelines.
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Early-summer tease arrives Sunday
The warmest day of the year is likely for much of southern Ontario on Sunday as warm, humid winds spread into the region. Enough instability could build that we may have to contend with more thunderstorms during the second half of the day.
Before this weekend, the warmest readings we’ve seen so far this year include:
26.1°C in Windsor on April 14
23.8°C in Hamilton on April 9
20.6°C in Toronto on March 13
19.9°C in London on April 14
![Ontario humidex Sunday](https://images.twnmm.com/c55i45ef3o2a/4j4swx0kazPw8cDM3sovNP/09e54e3e845fa558fca19149cdde96f4/Ontario_humidex_Sunday.jpg?w=3840&q=80&fm=webp)
Daytime highs on Sunday will soar into the mid-20s for many communities, with humidex values possibly cracking 30 around Windsor.
Given the warmth in the forecast, Toronto and London are on track to beat 2024’s high-mercury mark by Sunday, while Hamilton might fall short by just a hair.
We’ll see a renewed risk for showers and thunderstorms over southern Ontario during the day Sunday as this warm and unstable air builds in.
![Ontario Thunder Risk Sunday Afternoon](https://images.twnmm.com/c55i45ef3o2a/5xuE0Td3CjvgLaxZihBul2/309ae0bc52ea7b3c58df47d8966e69be/Ontario_Thunder_Risk_Sunday_Afternoon.png?w=3840&q=80&fm=webp)
This includes much of the Highway 401 corridor from Windsor to Kingston, including Toronto, as well as north toward Bancroft and Barrie. Look out for heavy rain and gusty winds in any of the feistier storms that bubble up on Sunday.
Warmth sticks around into early this week
Another rainy system tracking into northern and central Ontario on Monday will keep the unseasonably warm air parked over the southern half of the province to start the week. However, there’s uncertainty in just how warm things will get on Monday. We could see big temperature variations over short distances with clouds and lake breezes.
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We’ll see additional showers and possibly a risk for rumbles of thunder as that disturbance passes the region to the west.
Temperatures will likely start to moderate back toward seasonal as we head into the second half of the upcoming week. Warm-weather lovers may not have to wait long for above-seasonal conditions to return, as more unseasonable warmth could arrive in time for the beginning of May.
Header image courtesy of Solomon Hoasjoe.
Stay with The Weather Network for all the latest on your forecast across Ontario.