Johannesburg residents can unpack their lightweight wardrobe‚ because the first heat wave of the new season is bringing temperatures as high as 31 degrees.

"A heat wave with persistently high temperatures is expected in Gauteng and western parts of Limpopo province until at least Wednesday‚" the SA Weather Service said on Sunday.

It warned there was a risk of extremely high fire danger conditions over Gauteng‚ North West‚ south-western parts of Limpopo‚ western and southern parts of Mpumalanga‚ eastern parts of the Northern Cape and parts of the Free State.

Weather.com predicts a high of 29 degrees on Monday while Tuesday and Wednesday are expected to be 31 degrees. Thursday to Sunday are expected to have temperatures of between 26-28 degrees. Mostly cloudy conditions are forecast for Friday.