Recent above-average heat across western Saudi Arabia, with station readings near 42–44°C in late July and National Center for Meteorology guidance for sustained elevated temperatures in August, anchors trader focus on 38–39°C outcomes for Jeddah on August 5. Jeddah’s subtropical coastal setting features intense solar heating, Red Sea moisture that moderates overnight cooling, and typical August highs of 37–38°C, yet daily variability from steering winds and local pressure patterns can push peaks 1–3°C higher or lower. Ensemble models show modest spread around these values, while the 18.5% probability assigned to 40°C+ reflects residual upside risk from the current warm spell before the short-term forecast window closes.