Residents in Whitby, Ontario, can expect a pleasant start to the week before a weather system moves in on Tuesday, April 28, 2026, bringing rain and the risk of thunderstorms. According to Environment and Climate Change Canada, Monday offers a brief window for outdoor activities with mainly sunny skies and a high of 15°C.
The sunny conditions on Monday come with a high UV index of 7, so residents planning to spend time outside should take appropriate sun protection. The weather remains consistent with historical averages for this time of year, as local data from the Oshawa Executive Airport shows temperatures hovering near typical climate normals.
Conditions are expected to change Tuesday, as a new weather system arrives with 10 to 15 mm of rain and a risk of thunderstorms. The day will also bring gusty winds from the south reaching up to 50 km/h, with daytime temperatures climbing to 17°C.
Those heading out on the water should prepare for changing conditions on Lake Ontario. According to the Eastern Lake Ontario marine forecast, waves are expected to build to 1 metre this afternoon and reach 1 to 1.5 metres by Tuesday at noon. While gusty winds are expected, the official seasonal strong wind warning program has ended, meaning no formal marine warnings will be issued for these conditions.
