The country's meteorological agency put nine of Iran's 31 provinces on orange alert for at least the rest of the week, forecasting highs of up to 50C for several days in some areas.
High temperatures in Iran are common during the summer months, but reservoirs are depleted after repeated droughts and electricity supplies struggle to cope when air conditioners are cranked up in homes and workplaces.
The closure of banks, government offices and other public buildings on Wednesday will affect the provinces of Mazandaran, Markazi, Yazd, Semnan, Kermanshah and Razavi Khorasan, along with Tehran, local media said.
"Due to rising temperatures and the necessity of optimising and managing energy consumption, the activities of executive agencies in Tehran province will be closed on Wednesday," state broadcaster IRINN quoted Tehran Governor Mohammadsadeq Motamedian as saying.
Medical facilities, private companies and selected bank branches will remain open.
Last week, Iranian President Masoud Pezeshkian warned the country's excessive water consumption was untenable and could leave cities including Tehran with severe shortages by September.
In July 2024, during another severe heatwave, several provinces across Iran decided to close public offices for a few days to save on water and electricity.
with AP
