Current ensemble forecasts from sources like the GFS and ECMWF place Toronto's June 16 maximum in the 22–24 °C range, with modest spread driven by variable cloud cover, the timing of any weak frontal passage, and boundary-layer mixing under light winds. These conditions produce limited diurnal heating compared with clearer, more stable patterns, keeping values near the climatological mid-June average of roughly 23 °C. Official resolution will rely on Environment Canada’s Pearson Airport reading, where urban effects and exact observation timing can shift the recorded high by 1 °C. The closely matched market odds on 23 °C versus 24 °C therefore reflect genuine uncertainty in the final model runs and any last-minute changes in insolation or moisture.