Recent Environment Canada and numerical weather prediction model consensus point to a daily maximum near 22°C in Toronto on September 30 under mostly cloudy skies and light southerly flow, supporting the market's leading 38.5% implied probability for that exact outcome. Persistent mild air mass advection from the south has kept overnight lows in the mid-teens and daytime readings in the upper teens to low 20s through late September, with limited diurnal range expected amid high cloud cover. Ensemble spreads remain tight around 21–23°C, though minor timing differences in any weak frontal passage could shift the peak by 1°C. Updated short-range guidance and local observations tomorrow morning will provide the final calibration ahead of market resolution.