A heat warning is in effect across southern Ontario as a heat dome pushes temperatures into the low to mid-30s this week. “We’re under a heat warning as a heat dome moves into southern Ontario, with temperatures expected to climb into the low to mid-30s over the next few days,” said CTV News London meteorologist Julie Atchison. “With the humidex, it’ll feel like the mid-40s. We could tie today’s record high of 33 C, but Tuesday is expected to be the hottest day of the week, with Environment Canada forecasting a high of 35 C and humidex values in the mid-40s. “We’re expecting sunshine and a mix of sun and cloud through the week, with little relief from the heat and humidity until Thursday. Daytime highs heading into Friday and the weekend are expected to range between 28 C and 30 C,” Atchison added. The local health unit also advises to drink plenty of water, seek shade and take precautions if you’re spending time outdoors. Extreme heat and humidity can be especially dangerous for older adults and young children.