Traders see the highest temperature in Jeddah on August 23 clustered around 38–39 °C because short-range global models (GFS, ECMWF) currently indicate a typical late-summer pattern dominated by the subtropical high, with minimal cloud cover and light northerly flow off the Red Sea. Official guidance from regional meteorological centers and ensemble means place daytime maxima near 38–40 °C (roughly 100–104 °F), consistent with climatological August averages of 37–39 °C for the coastal station. The tight spread between the 37 °C, 38 °C, 39 °C, and 40 °C contracts reflects remaining uncertainty in boundary-layer mixing and any brief afternoon sea-breeze modulation that could trim or add 1 °C to the peak reading. With landfall or significant moisture advection unlikely before the 23rd, the market-implied distribution largely captures this narrow forecast envelope rather than any major regime shift.