Environment Canada has upped its warnings to the public to extreme in the Muskoka area.

Beginning Saturday and continuing through next week, daytime highs are forecast to reach the low to mid-thirties with humidex values into the mid-forties. Overnight low temperatures are expected to be in the low twenties, except high teens in some rural areas, providing little relief from the heat.

Current indications suggest hot temperatures could persist through next week. This will be the most significant heat event in the past few years.

Extreme heat affects everyone.

The risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors.

Watch for the effects of heat illness: swelling, rash, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to ONstorm@canada.ca or tweet reports using #ONStorm.