Official forecasts and ensemble models point to a high of 28–29°C in Toronto on September 1 as the most probable range, driven by a transitional pattern following cooler, rainy conditions on August 30–31. Southerly flow and partial clearing are expected to support modest warming, while scattered showers or lingering cloud cover introduce uncertainty that could limit peak temperatures to the mid-20s or allow brief spikes higher. This aligns with climatological norms near 24–25°C but reflects current model consensus favoring slightly above-average values amid variable moisture and limited instability. Traders assign the tightest probabilities to 27–29°C outcomes precisely because small differences in convective timing or boundary-layer mixing can shift the daily maximum by 1–2°C, consistent with the spread across deterministic and ensemble guidance.