Jeddah’s coastal desert setting along the Red Sea produces typical late-August daily maxima of 37–39 °C, with trader sentiment clustered on these outcomes because current model guidance from sources such as the National Center for Meteorology points to a peak near 38 °C on the 25th under mostly sunny skies and light northwesterly flow. Onshore breezes and marine-layer moisture often cap extreme heating, while any southeasterly shift advecting hotter air from the interior can add 1–2 °C; conversely, increased afternoon cloud cover or stronger sea-breeze timing can hold the official reading to 37 °C. Short-range forecast uncertainty, measurement precision at the King Abdulaziz International Airport station, and minor model spread in boundary-layer mixing explain the tight spread between the 37 °C, 38 °C, and 39 °C contracts.