Forecast models from multiple sources converge on a daily high near 35–36°C for Jeddah on September 30 under clear skies, light westerly winds, and high humidity from Red Sea moisture, producing heat indices well above the actual air temperature. Typical September climatology supports afternoon peaks in this range, with minimal cloud cover and stable high pressure limiting convective cooling or rain. Slight model-to-model differences in peak timing and local sea-breeze effects create the near-even split between 35°C and 36°C implied probabilities, while lower odds on 37°C or above reflect limited potential for stronger heating or measurement variance at official stations. Updated observations through midday will refine the final recorded maximum.