Recent forecasts from models and agencies place Jeddah’s June 13 maximum near 36–37°C under typical early-summer high pressure, clear skies, and strong solar insolation, yet the equal 22.5% market weighting on 37°C, 38°C, and 39°C reflects genuine uncertainty in boundary-layer moisture from the Red Sea and subtle wind shifts that can suppress or enhance daytime heating by 1–2°C. Historical June averages of 36–39°C provide the baseline, while variable marine-layer depth or light northerly flow can cap peaks below 38°C or allow brief excursions to 40°C. Updated model runs and official observations in the next 48 hours will clarify whether conditions trend toward the lower or upper side of this narrow range.