**Forecast models indicate a likely overnight low near 28–30°C for Jeddah on September 22, driven by persistent high pressure, light winds, and high humidity from the adjacent Red Sea that limits nocturnal radiative cooling.** Clear skies typical of late-summer conditions in this hot desert climate allow some temperature drop after sunset, yet dew points near 25–26°C keep the air mass warm and stable, consistent with September climatology showing average minima of 27–29°C. Recent observations and ensemble guidance show minimal day-to-day shifts, with no incoming troughs or stronger onshore flow expected to alter the pattern before resolution. The closely matched market probabilities around 25°C or below versus 35°C or higher, alongside clustered 26–34°C outcomes, reflect trader focus on small uncertainties in exact minimum timing, local microclimate effects at the reporting station, or minor model spread in boundary-layer mixing. Updated short-range runs and official observations in the next 48 hours will provide the clearest signals for positioning.