Heat warning in effect for parts of central Ontario

A man is seen cooling off in the shade reading a book in this undated file image.

While eastern parts of central Ontario can expect cooler temperatures today, several areas to the west are still under a heat advisory.

Environment Canada has issued a heat warning for Orangeville, Grand Valley, Southern Dufferin County, Dundalk and Southern Grey County.

The national weather agency says a prolonged heat event will continue for those areas today, with hot and humid conditions expected.

Afternoon highs will range between 29 to 31 degrees Celsius with humidex values at 37 to 40.

Nighttime will offer little relief with lows expected in the 20 to 23 range with humidex values of 26 to 30.

Temperatures and humidex values may be several degrees cooler near the shores of the Great Lakes.

Less hot and humid conditions are expected to slowly move into the area this weekend.