**Trader consensus at 100% for 23°C as Toronto's October 1 high reflects official observations from Environment Canada and regional stations confirming a peak near 22.8–23°C under mostly cloudy skies with southwesterly flow.** This exceeded the 1991–2020 climatological average high of 18.5°C, driven by a transient warm air mass ahead of an approaching frontal system that delivered light rain later in the period. Model runs from GFS aligned closely with surface readings, showing minimal diurnal range and dew points supporting sustained warmth through afternoon. Scenarios that could have altered the outcome, such as stronger cold advection or measurement discrepancies at Pearson versus downtown sites, did not materialize, locking in the market-implied resolution.