If you feel like this Summer hasn't been hot enough, Tuesday's forecast will make you very happy.
Environment Canada has Toronto, parts of the GTA and much of southwestern Ontario under a heat warning.
Humidex values are going to hit 40 degrees in the afternoon, along side highs of 30.
The weather agency says thunderstorms are possible in the afternoon, and because of this heat, they may be severe.
A cold front will sweep across the regions Tuesday evening bringing a return to near seasonal temperature values for the remainder of the week.
While extreme heat can put everyone at risk from heat illnesses, health risks are greatest for older adults, infants and young children. It's also trying for those with chronic illnesses such as breathing difficulties, heart conditions or psychiatric illnesses, or people who work in the heat, exercise in the heat, don't have access to air conditioning and those who are homeless.
Watch for symptoms of heat illness, which include dizziness or fainting, nausea or vomiting, headache - rapid breathing and heartbeat, extreme thirst and decreased urination with unusually dark yellow urine. if you experience any of these symptoms during extreme heat, immediately move to a cool place and drink liquids.