The Toronto District School Board says that it won’t cancel classes due to the sweltering heat but will nonetheless do everything else within its means to “alleviate some of the discomfort being experienced by students and staff.”

The TDSB sent a letter to parents on Tuesday, in which it outlines some of the steps it is taking to help students and staff at schools without air conditioning amid a rare fall heat wave that has seen temperatures surpass the 30 C threshold for the last four days in a row. The TDSB says that only 125 of its 584 schools are fully air-conditioned, something it would cost “hundreds of millions” to fully rectify.

“At this time, the forecast suggests that the high temperatures will continue into tomorrow, but cool off for the remainder of the week. Until then, please know that we are fully aware of the discomfort being felt within our schools and are working to help manage the situation as best we can until the temperature drops,” the letter states.

The TDSB said that it is working to mitigate the heat by using fans to provide air movement, keeping doors and windows open and reducing strenuous activities such as gym classes.

The board says that it is also rotating staff and students into air conditioned areas within schools, when available.

There are currently 12 TDSB elementary schools outfitted with so-called cooling centres under a long-term project that began last year. The TDSB hopes to install cooling centres in all of its school without air conditioning over the next five to seven years.

In its letter to parents, the TDBSB said it is doing “everything” within its means to make schools more comfortable amid the extreme heat but won’t cancel classes, despite some requests for them to do so.

“We have been asked about closing schools during extreme heat. This decision would put thousands of parents across Toronto in a challenging position of having to find childcare with very short notice — something we know will not be possible in every case. Therefore, the TDSB and other school boards across Ontario do not typically close schools due to heat,” the letter states.

The letter from the TDSB comes one day after the Elementary Teachers’ Federation of Ontario called on the board to do more to address the hot and humid conditions in many classrooms.

The ETFO said that the conditions in some classrooms are “unbearable” and are having an “unacceptable toll on teaching and learning.”

Meanwhile, the heat has resulted in record electricity use among customers that do have air conditioning units. Demand hit 21,786 megawatts province-wide on Monday, which represents peak usage. The typical usage in late September is about 18,000 megawatts a day.

Environment Canada is forecasting a high of 28 C on Wednesday but the temperature is expected to drop down to a more seasonal 19 C on Thursday.