Clear skies and northwesterly winds are steering cooler continental air into the Toronto region on October 5, 2026, supporting market-implied odds favoring an 8°C low. Official forecasts from Environment Canada and model consensus show daytime highs near 14–16°C under mostly sunny conditions, with overnight radiational cooling expected to bottom out near 5–9°C amid light winds and low humidity. Historical climatology places the average October 5 low at about 9.9°C, so current guidance reflects a modest cool anomaly without extreme cold-air advection. Traders appear to weigh the tight spread between the 8°C and warmer-binned outcomes against minor model variability in boundary-layer mixing and exact wind timing, with resolution hinging on the official minimum recorded at Pearson or downtown stations before midnight.