Irkutsk weather in September

September in Irkutsk: cool, a little rain, with clean air — a great time to visit.

#5 of 12 months in Irkutsk · #357 of 604 destinations to visit in September · comfort 77/100 (tier B)

Updated June 2026 · climate normals from ERA5 reanalysis

Irkutsk climate normals — September

Daytime high16°C / 61°F🙂 cool
Nighttime low6°C / 44°F
Feels like (high)14°C / 57°F
Rainfall69 mm / 2.7 in🌦 some rain
Rainy days10 days
Humidity72%💧 humid
Dew point6°C / 43°F
Sunshine8.5 h/day
Daylight12.6 h
Wind15 km/h / 9 mph
Snowfall0.7 cm / 0.3 in
Air quality (US AQI)28🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Where is Irkutsk?

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Irkutsk in September — FAQ

Is September a good time to visit Irkutsk?
September in Irkutsk: cool, a little rain, with clean air — a great time to visit. It ranks #5 of 12 months for Irkutsk on SeasonMap's comfort score (77/100).
What is the weather like in Irkutsk in September?
In September, Irkutsk averages a daily high of 16°C and a low of 6.4°C, with about 68.8 mm of rain over roughly 10.4 rainy days.
What is the air quality in Irkutsk in September?
Irkutsk has a mean US Air Quality Index of about 28 in September.

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