Environment Canada’s latest forecast for October 2, 2026, calls for a high of 20 °C under a mix of sun and cloud with a 30 % chance of showers, driven by a northwest flow behind a departing frontal system. Ensemble guidance and recent model runs show modest spread around this value, with some solutions allowing brief clearing that could push readings to 21–22 °C while others keep more cloud and showers capping the maximum near 19 °C. Steering winds, boundary-layer mixing, and the precise timing of any showers remain the key variables that differentiate the closely matched 20 °C and 21 °C outcomes priced by traders. Updated model cycles and morning observations on October 1 will further narrow the range ahead of market resolution.