Current forecasts from Environment Canada and ensemble models indicate a minimum temperature near 12°C for Toronto on September 19, driven by increasing easterly to northeasterly flow, cloud cover limiting daytime heating, and modest nocturnal radiative cooling under partly to mostly cloudy skies. Trader sentiment splits nearly evenly between sub-6°C and 15°C+ outcomes because of model spread in boundary-layer mixing and precipitation timing—stronger onshore winds could suppress cooling toward 10–13°C, while clearer breaks or lighter winds might allow dips below 8°C. Mid-September climatology shows typical overnight lows of 10–14°C, underscoring how small shifts in steering patterns or dew-point advection create the observed 45–47% implied probabilities on the extremes. Updated model runs and official briefings over the next 48 hours will likely resolve the range.