Trader sentiment for Toronto's peak temperature on May 16 centers on the closely matched 20 °C and 21 °C outcomes because official forecasts project a daytime high near 22 °C under partly cloudy skies with a 40 % chance of showers. These conditions introduce uncertainty through variable cloud cover that limits solar heating and potential convective showers that enhance evaporative cooling, keeping peaks from exceeding the mid-20s. The tight spread between the leading probabilities reflects model differences in shower timing and moisture advection from the Great Lakes, while lower odds for 22 °C or higher align with moderate southwesterly flow that prevents rapid warming. Historical May climatology at Toronto Pearson, with average highs near 18–20 °C, provides additional context for why traders assign minimal probability to extremes.