Recent official forecasts from Environment Canada and other models indicate a daily minimum near 14–15°C for Toronto on September 12 under a mix of sun and cloud with a 40% chance of showers, driven by southerly flow ahead of an approaching frontal system. This places the expected low well above 10°C while remaining below 20°C, creating the near-even split in market-implied odds between those broad outcomes. Key differentiating factors include the precise timing of any shower-cooled air masses, overnight wind speeds that could enhance or suppress radiational cooling, and minor model disagreements on boundary-layer moisture. Historical September climatology shows typical overnight lows in the low teens, so traders are weighing whether current warm advection will hold or if brief clearing allows faster temperature drops. Updated model runs and Environment Canada briefings over the next 48 hours will likely resolve the narrow range around 13–15°C.