Burlington residents can look forward to above-normal temperatures and mostly clear skies this week before a chance of thunderstorms arrives Tuesday, according to Environment Canada and The Weather Network.
Monday, June 8, 2026, is expected to reach a high of 25°C under sunny skies, though areas near Lake Ontario will stay cooler at 16°C. The humidex will make it feel like 28°C inland. The UV index is forecast at 9, or very high, meaning anyone spending time outside should wear sunscreen, a hat, and seek shade during midday hours.
Overnight lows will settle around 15°C, with sunset coming late at 8:57 PM, giving residents plenty of daylight for evening activities. But the pleasant conditions come with a caveat: lake water temperatures near Burlington remain around 10.8°C, which is considered very cold and unsafe for comfortable swimming. The warmest lake temperatures typically do not arrive until August.
Tuesday will be sunny early in the morning, then a mix of sun and cloud, with a high near 29°C — though lakeside areas will again be cooler at 21°C. Conditions shift in the afternoon: The Weather Network says there is an 80 to 90 percent chance of showers and a risk of thunderstorms, with 5 to 10 millimetres of rain possible Tuesday evening. Temperatures will stay mild overnight, with a low near 18°C.
The heat builds through the second half of the week. By Thursday, highs could hit 30°C, well above the normal June high of 23°C. Humidity will also rise, making it feel like 40°C. Those near the lake will still get some relief from the cooling breeze off the water, as lakeside areas often run several degrees cooler than inland neighbourhoods.
