Melbourne expected to sizzle as temperatures rise

Melbourne's weather is expected to sizzle over the next few days with the mercury set to near 40 degrees on Monday.

The Bureau of Meteorology has forecast 31 degrees on Sunday and a whopping 38 degrees on Monday.

Kidsafe Victoria general manager Jason Chambers said now is the perfect time to remind parents and carers never to leave children in hot cars.

"The temperature inside a car can be 20 to 30 degrees warmer than the outside temperature," he said.

"Based on Monday's forecast, the temperature inside a parked car could easily reach over 50 to 60 degrees in a matter of minutes."

He said small children were particularly at risk when left in a hot car because they can lose fluid quickly, become dehydrated and suffer from heat stroke, which can be life-threatening.

Melburnians will get relief from the warmer weather with a thunderstorm also predicted for Monday afternoon and evening.

Tuesday is expected to be a lot cooler too, with a top of 19 and 90 percent chance of rain.