Egyptian meteorologists expect moderately hot weather to last throughout Eid Al-Fitr, the three-day national Islamic holiday which marks the end of the holy month of Ramadan on Wednesday.
A slight rise in temperatures is forecast countrywide, with Eid's temperatures predicted to be 1-2 degrees Celsius higher than Tuesday's 36 C temperatures.
The high for the capital is forecast to be 37 C on Wednesday and Thursday, with a low of 25 C expected both days.
High temperatures of 38 C and lows of 29 C are forecast in the popular south Sinai resort of Sharm El-Sheikh.
Weather will be hotter in the ancient temple city of Luxor in Upper Egypt, with a high of 42 C and a low of 26 C.
Forecasters say high sea levels at the Mediterranean, Red Sea and the Gulf of Suez will result in rough waters for fishing or navigation on Wednesday.
They warned about poor visibility on roads Wednesday due to heavy morning fog.