Recent ensemble forecasts from Environment Canada and global models such as GFS and ECMWF indicate a daytime high near 23°C in Toronto on May 17, driving the leading market-implied probability of 28 percent. This reflects gradual warming from midweek’s cooler conditions under strengthening southerly flow that enhances boundary-layer mixing and solar insolation during peak afternoon hours. Minor uncertainties around cloud cover and residual moisture could limit peaks to 22°C or allow brief excursions to 24°C, which accounts for the closely bunched probabilities across the 22–24°C range. Official high-resolution updates expected later today and tomorrow morning will further clarify these variables before resolution at Pearson International Airport.