Official forecasts from Environment Canada indicate clear skies and light winds overnight into August 21, supporting a minimum near 16°C under a stable warm air mass typical for late summer in southern Ontario. Radiative cooling under clear conditions and modest humidity levels are the dominant factors differentiating outcomes in the 12–17°C range, with small variations in wind mixing or cloud cover timing able to shift the exact low by 1–2°C. Historical August minima average around 16°C, providing context for the tight clustering of market-implied odds on 14°C and 15°C, while the low probabilities assigned to extremes below 11°C or above 18°C reflect the narrow forecast envelope and limited potential for significant cold advection or heat buildup on this date. Updated model runs and real-time observations near resolution will refine the final recorded minimum.