**Forecast models and observational data indicate peak temperatures in Jeddah on September 10, 2026, are most likely to reach 37–38°C, consistent with the closely matched market-implied odds of 36% and 34.5%.** Jeddah’s Red Sea coastal location produces a hot, arid climate where daytime maxima in September typically average near 35–37°C, driven by high solar insolation near the equinox, light to moderate westerly winds, and low cloud cover that allows strong surface heating. Recent hourly observations show temperatures climbing from the low 30s°C in the morning to afternoon peaks, with partial cloudiness and dew points around 20–23°C limiting extreme excursions above 39°C while preventing rapid cooling. Model consensus across sources points to a narrow window around midday–early afternoon for the daily high, where small differences in wind speed, humidity advection from the sea, or brief cloud build-up can shift the exact maximum by 1–2°C. Historical September records in the city show similar variability, with recent days recording highs of 36–38°C under comparable stable, mostly clear conditions. Updated National Meteorological Center or equivalent regional guidance on afternoon observations will provide the final verification for market resolution.