Official meteorological observations for Toronto on May 21 recorded a daily high near 15 °C, well below the seasonal average of about 20 °C. This outcome reflects a cooler-than-normal air mass advected by northerly flow, limiting daytime warming under mostly sunny skies with light winds. Environment Canada and local stations documented maximum temperatures in this narrow range, aligning with the market’s near-certain pricing for the 15 °C outcome and negligible odds for 18 °C or higher. While minor variations can occur across micro-sites or measurement timing, the consensus data from authoritative networks leave little room for revision unless official post-event adjustments alter the reported maximum.