Environment Canada has issued a heat warning for southern Ontario that’s expected to last until Tuesday. In the London, Ont. region, highs are forecast at 30 degrees, feeling closer to 35 Sunday. The Middlesex-London Health Unit (MLHU) is advising the community to be prepared, take precautions to be safe, and check in on family, friends, and neighbours. According to Environment Canada, the hottest day is expected Monday. It will feel like close to 40 degrees for Londoners. For a list of cooling centres across London, head to the city’s website. Here’s a look at the rest of the forecast Sunday: Mainly cloudy. 30 per cent chance of showers early this morning with risk of a thunderstorm. Clearing near noon. High 30. Humidex 35. Sunday night: Clear. Fog patches developing overnight. Low 21. Monday: Sunny. Fog patches dissipating in the morning. High 31. Humidex 39. Tuesday: A mix of sun and cloud with 30 per cent chance of showers. High 28. Wednesday: A mix of sun and cloud with 40 per cent chance of showers. High 26. Thursday: Sunny. High 25.