Recent forecasts for Jeddah on September 16 center on a daily maximum of 37–39°C under clear skies and light winds, aligning with the tightly clustered market odds around those levels. Persistent high pressure supports strong solar heating over the Red Sea coast, where typical September maxima average near 36–38°C amid elevated humidity that can slightly suppress peak readings through increased latent heat flux. Minor differences in model guidance hinge on exact sea-breeze timing and boundary-layer mixing, which can shift the afternoon high by 1–2°C. With no significant cloud cover or synoptic disturbances expected, traders are pricing the narrow uncertainty band between stable hot conditions and subtle local variations that determine whether the peak registers at 37°C, 38°C, or 39°C.