If you're grumbling about the extended cold across southern Australia this winter, spare a thought for people in the Middle East who are sweltering through heat that's rarely been recorded before.

While it might be snowing in Hobart and Melbourne might be expecting a top of just 11 degrees on Monday, Iraq was forced to declare a four-day holiday from last Thursday to help residents cope with extreme conditions as a heat dome set in over the region.

The Iranian port city of Bandar-e Mahshahr recorded an apparent temperature of as much as 74 degrees on Friday. That remarkable reading came from a heat index that is calculated according to a formula that combines the air temperature - 46 degrees at its peak - with the top humidity or dew-point temperature reached of 32 degrees.

Dew point levels above 26 degrees are considered oppressive as the body struggles to lose heat through perspiration.