September in Tehran averages a daily high of 32.2°C with nights around 20.6°C. Rain is rare — about 0.8 wet days and 1.8mm across the month. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Tehran is April.
Based on TEHRAN MEHRABAD, IR (9.5km), 1995–2024. 18 years of September data.