Environment Canada has updated its heat advisory for southern Ontario, warning about high humidex values.

The agency says with the humidity Monday, it will feel like 43.

The air temperature will be 30 or above until Friday when a cold front is forecast to pass through southern Ontario.

We could also see a cold front Monday afternoon, which will bring a cooler and less humid air mass.

However, daytime highs are still expected in the low thirties in the next two days.

Overnight low temperatures in the high teens will some relief from the extreme heat.

Environment Canada warns this extreme heat event will continue though for most of the week, calling this streak the most significant heat event in the past few years.