**Market-implied odds cluster tightly around 17–19°C for Toronto’s daily minimum temperature on August 22, 2026, reflecting model consensus for a typical late-summer overnight low under a warm, moist air mass.** Environment Canada and long-range guidance point to daytime highs near 25°C with overnight lows in the 16–18°C range, influenced by a pattern of isolated thunderstorms and generally above-average warmth persisting through mid-to-late August. Key scientific differentiators among the closely matched outcomes include overnight radiative cooling rates, modulated by cloud cover, wind speed, and boundary-layer moisture. Clear or partly cloudy skies promote greater longwave radiation loss and lower minima, while increased low-level humidity or light winds from Lake Ontario’s moderating influence (urban heat island effects notwithstanding) can limit cooling to the higher end of the range. Recent thunderstorm activity noted in forecasts may enhance localized mixing or add cloudiness that traps heat, keeping the minimum from dropping below 17°C. Historical climatology shows August overnight lows averaging near 17–18°C, so traders are weighting current model runs and the absence of strong cold-air advection. Resolution hinges on the official Environment Canada or equivalent station reading; small forecast shifts in dew point or wind could easily separate 17°C from 19°C outcomes.