**Forecast models from sources like WeatherBug, PredictWind, and Yr.no indicate a peak temperature for Jeddah on September 18, 2026, most likely between 36–38°C.** This stems from stable high-pressure conditions typical for the Red Sea coast in mid-September, with sunny to mostly sunny skies, light westerly winds, and moderate humidity around 50–65% limiting extreme heating while sustaining high daytime values. Recent observations show highs near 37–41°C in the preceding days, aligning with climatological September averages of 35–37°C at Jeddah King Abdulaziz International Airport. Subtle differences among models—such as timing of peak insolation, minor wind shifts, or localized moisture—create the close spread between 36°C, 37°C, and 38°C outcomes. Traders' tight clustering around these figures reflects the narrow expected range and low precipitation risk, with 39°C+ remaining plausible only if heating exceeds current guidance.