Toronto temperatures are expected to remain in the high temperatures for the next three of four days. (Dwight Friesen/CBC)

Toronto has declared its first extreme heat alert of the summer — while city services are virtually shut down by a civic workers strike.

Temperatures are forecast to reach 30 C on Wednesday and to stay in the high 20s for the next three or four days. The heat alert, the city says, will stay in place until further notice.

However, many of the city-run cooling centres — where residents and their pets can cool off and get a cold drink — are closed because of the strike by 24,000 municipal workers.

Instead the city is telling people to go to "make use of air conditioned shopping malls and local libraries as places to cool off."

A section of the Metro Toronto Convention Centre will also remain open 24 hours a day during the time the alert is in place.