It may be the first day of fall, but Environment Canada has issued a heat warning for Waterloo region and Wellington County.  

Temperatures are expected to rise as high as 31 C Saturday, 32 C Sunday, but on both days the humidity could make it feel more like 40.

The unseasonably warm temperatures are expected to persist into the beginning of next week, with Monday's high forecasted at 29 C.

Young children, pregnant women, older adults, people with chronic illness and those working or exercising outdoors are at greater risk of heat illnesses, such as heat stroke or heat exhaustion, according to Environment Canada.

The weather agency also warns people against leaving pets or people inside parked vehicles during periods of intense heat.