Recent forecasts for Jeddah show daytime highs clustered in the mid-to-upper 30s °C for September 16, consistent with seasonal norms near 36–37 °C, yet small differences in model outputs create broad uncertainty across 35–41 °C. Primary drivers include Red Sea humidity moderating overnight lows while allowing strong diurnal heating under mostly clear skies, variable sea-breeze timing, and light wind shifts that can alter peak temperatures by 1–2 °C. With no significant weather systems or cloud cover expected, the closely matched market probabilities reflect genuine forecast spread in maximum readings rather than any single dominant catalyst, with updated model runs and local observations likely to narrow the range before resolution.