Great Southern towns to hit 42C

The Great Southern is set to sizzle this weekend with forecast maxima of more than 40C in several towns.

Kojonup, Katanning and Lake Grace are set to hit 42c on Sunday following 38C on Saturday.

Mt Barker is forecast to hit 41C on Sunday, which forced the cancellation of the $100,000 Mungrup Stud Spirnt at Mt Barker Turf Club.

On the south coast, tempratures will peak at 33C in Albany and 34C in Denmark on Sunday.