Toronto Warms to 28 C by Thursday as Sunny Stretch Lifts Mid-September Temperatures

The city is tracking a brief, above-seasonal burst that gives way to a late-week cooldown.

Overview

Environment Canada projects highs near 24 C early in the week, rising to 26 C Wednesday and about 28 C Thursday under mostly clear skies.
Overnight temperatures are forecast to hold in the mid-teens during the warm spell, keeping nights milder than usual.
A cooler, cloudier pattern is expected to move in late in the week, with a city low near 9 C possible Friday night and no rain anticipated early in the period.
This stretch sits several degrees above typical mid-September norms of 22 C by day and 14 C by night.
Even with the warmth, the outlook remains below the Sept. 18 record of 31.1 C set in 1942, and recent years were cooler, with 2023 at 19–23 C and 2024 reaching 25 C only once during this week.