Hot weather is expected across most of Ontario from Friday through Sunday, Environment Canada reports.
Toronto and Ottawa will see daily highs near 32 C each day, with nighttime lows not dropping below 19 C.
Humidity will push humidex values to around 38 to 40 during afternoon hours, officials say.
Heat alerts remain in effect at the "excessive heat" level, particularly for vulnerable populations.
Residents are encouraged to stay well‑hydrated and limit outdoor activity during midday heat.
Officials also recommend checking on elderly relatives frequently.
Public cooling centres are open from sunrise to sunset for those in need.
Travelers should keep water bottles and wear breathable clothing.