Official observations from Environment Canada stations in the Toronto area recorded a daily maximum of 28°C on August 4, 2026, under mostly sunny conditions with light winds, directly supporting the market's near-certain outcome. This value aligns with late-summer climatology for the region, where highs typically range 24–29°C absent strong frontal systems or heat domes. Recent model runs from the Global Deterministic Prediction System showed minimal day-to-day variability leading into the date, reinforcing trader consensus. Minor uncertainty remains around precise station selection or rounding conventions used for resolution, though historical precedents indicate such differences rarely exceed 1°C.