A public holiday was declared Monday for Baghdad and southern Iraq as the mercury hit 50 degrees Celsius (122 Fahrenheit) at the start of the holy Muslim fasting month of Ramadan.
The head of Iraq's Meteorological Office said temperatures were expected to rise further on Tuesday and Wednesday before finally giving people some respite later this week.
A parliamentary official said the holiday for public sector workers had been declared for Baghdad, Diyala province in central Iraq, and all of the south of the country, "because of the increased temperature."
It is the first time Iraq has taken such a step, the official said, speaking on condition of anonymity.
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Meteorological Office chief Ali Karim said the temperature hit 50 degrees Celsius in Baghdad and southern Iraq on Monday, and "will be higher tomorrow and the day after" but he did not give specific estimates.
He added that the temperature rose as high as 50.6 degrees Celsius in 2010.
The rise in temperatures coincides with the beginning of Ramadan, when Muslims fast from dawn until dusk. Ramadan begins on Monday for Sunni Muslims, and on Tuesday for Shiites.
Summer in Iraq also typically brings with it a decline in electricity supply from the national grid, meaning Iraqis must rely more on private generators to power their air conditioners and fridges through the rising temperatures.
Frustration over poor power provision at the peak of summer spurred Iraqis to take to the streets in violent rallies across the south of the country last summer.