Irkutsk weather in September

In September, Irkutsk sees average daytime highs of 15°C and overnight lows near 6°C, with 61 mm of precipitation across 10.2 wet days and about 12.4 hours of daylight. It is the 5th-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 18°C in the first days to 12°C by the end. The sky is clear or mostly clear about 29% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 24 min at the start of September to 11 h 24 min by month's end. Set against the rest of the year, September is Irkutsk's 5th-clearest and 3rd-windiest month. For the whole year in context, see Irkutsk's year-round climate.

Daytime high
15°
5th warmest
Overnight low
9th coldest
Precipitation
61 mm
10.2 wet days
Daylight
12 h 24 min
6:45 AM – 7:09 PM
Cloud cover
60%
5th clearest
Wind
10 km/h
3rd windiest
Solar energy
3.47 kWh/m²
Travel score
4.6
out of 10

Irkutsk is capital city of Irkutsk Oblast, Siberia, in eastern Russia.

Density
2,252/km²
people per km²
Founded
1661

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 18°C in the first days to 12°C by the end.

A typical September day in Irkutsk reaches about 15°C in the afternoon and slips back to 6°C overnight — a 10°C spread between the day's warmth and the night's chill. On most days the high lands between 9°C and 21°C. Set against its neighbours, September runs about 6°C cooler than August and about 8°C warmer than October.

10°20°151015202530
Avg high (°C)Avg low (°C)
1199
2199
3189
4189
5188
6188
7178
8178
9177
10177
11167
12167
13166
14166
15156
16156
17155
18155
19145
20145
21144
22144
23134
24134
25133
26133
27123
28123
29122
30122

How September really feels in Irkutsk

Once humidity and wind are folded in, September averages 0 days that feel above 32°C and 3 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
3
wind chill below the day's low

The story in September is cold — wind chill drags the overnight "feels like" below the raw low.

Irkutsk weather by month

How September compares with the rest of the year at a glance. September is the 5th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-15° / -24°51.83.380.0
Feb-10° / -21°51.83.29.50.0
Mar-0° / -13°103.44.411.50.0
Apr / -3°225.73.613.61.7
May16° / 388.91.415.45.0
Jun21° / 10°6510.3016.46.4
Jul23° / 14°9412.20166.5
Aug21° / 12°10111.6014.56.3
Sep15° / 6110.20.612.44.6
Oct / -2°235.73.910.31.1
Nov-4° / -11°1345.38.50.0
Dec-13° / -20°103.55.27.50.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 29% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 54%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14456
24456
34456
44456
54555
64456
74456
84555
94555
104555
114654
124654
134654
144753
154753
164753
174852
184753
194753
204753
214753
224753
234654
244654
254654
264753
274654
284654
294654
304654

Chance of precipitation in September

Any precipitationSnow

Irkutsk gets around 61 mm of rain and snow over 10.2 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 33% and peaks near 37% on the wettest days, and about 1 day brings snow. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)Snow chance (%)
1370
2371
3371
4361
5361
6361
7361
8361
9361
10361
11351
12351
13341
14341
15342
16332
17332
18332
19322
20322
21323
22313
23313
24303
25294
26284
27284
28275
29275
30265

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 96% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
183161
284151
387130
489110
590100
69190
79370
89460
99550
109640
119730
129820
139820
149910
159910
1610000
1710000
1810000
1910000
2010000
2110000
2210000
2310000
2410000
2510000
2610000
2710000
2810000
2910000
3010000

Wind in September

Winds average 10 km/h in September.

Across September, daily wind ranges from about 9 km/h on the calmest days to 10 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
2010calm
2110calm
2210calm
2310calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 24 min at the start of September to 11 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 120 minutes over September. Sunrise moves from 6:20 AM to 7:09 AM, and sunset from 7:45 PM to 6:35 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.46:207:45
213.46:217:43
313.36:237:41
413.26:257:38
513.26:267:36
613.16:287:34
713.06:307:31
813.06:327:29
912.96:337:26
1012.86:357:24
1112.76:377:21
1212.76:387:19
1312.66:407:17
1412.56:427:14
1512.56:437:12
1612.46:457:09
1712.36:477:07
1812.36:497:04
1912.26:507:02
2012.16:526:59
2112.16:546:57
2212.06:556:54
2311.96:576:52
2411.86:596:50
2511.87:016:47
2611.77:026:45
2711.67:046:42
2811.67:066:40
2911.57:086:37
3011.47:096:35

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.47 kWh/m².

For context, solar energy here swings from a low near 0.91 kWh/m² to a high of 6.06 kWh/m² in June across the year — September's 3.47 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.1Bright
24.1Bright
34.0Bright
44.0Moderate
53.9Moderate
63.9Moderate
73.9Moderate
83.8Moderate
93.8Moderate
103.7Moderate
113.7Moderate
123.6Moderate
133.6Moderate
143.6Moderate
153.5Moderate
163.5Moderate
173.5Moderate
183.4Moderate
193.4Moderate
203.3Moderate
213.3Moderate
223.2Moderate
233.2Moderate
243.1Moderate
253.1Moderate
263.1Moderate
273.0Moderate
283.0Moderate
293.0Moderate
302.9Moderate
Planning a trip in September

Is September a good time to visit Irkutsk?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

4.6
Sightseeing
5th-best month of the year
0.7
Beach & pool
5th-best month of the year

September is a reasonable time to visit Irkutsk for sightseeing.

What to pack for Irkutsk in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Irkutsk sees daytime highs around 15°C and nights near 6°C. Worth packing: a warm layer and rain gear. About 10 days see rain.

a warm layerrain gear

UV index in Irkutsk in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Irkutsk peaks around July 12 at about 7 (high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 19 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 6 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJul 12UV 7Dec 19UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar2Moderate
Apr5Moderate
May5High
Jun6High
Jul7High
Aug5Moderate
Sep4Moderate
Oct2Low
Nov1Low
Dec1Low

Air quality in Irkutsk in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Irkutsk is worst in May — around 22 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (November, 10 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodMay 1621 µg/m³Nov 1510 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb15Moderate
Mar13Moderate
Apr17Moderate
May22Moderate
Jun16Moderate
Jul18Moderate
Aug18Moderate
Sep11Good
Oct12Good
Nov10Good
Dec12Good
Location & terrain

Where is Irkutsk?

Irkutsk sits at 52.3°N, 104.3°E, 415 m above sea level, in Russia. The nearest listed city is Markova, 11 km away.

Topography around Irkutsk

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Irkutsk.

Within 3 km, the terrain around Irkutsk has only modest variations in elevation — a maximum elevation change of 104 m around an average of 442 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 204 m; within 80 km, large variations in elevation — a maximum elevation change of 1,089 m.

The land around Irkutsk is covered by artificial surfaces (54%) and trees (27%) within 3 km, trees (58%) within 16 km, and trees (69%) within 80 km.

3 km
104 m
16 km
204 m
80 km
1,089 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Markova 11 km · Shelekhov 16 km · Angarsk 39 km · Usol’ye-Sibirskoye 67 km · Slyudyanka 81 km · Baykal’sk 87 km · Cheremkhovo 125 km · Gusinoozyorsk 189 km

Russia travel facts

Travel advisory
Level 4
Do Not Travel
Power plugs
Type C / F
230 V · 50 Hz
Prices
≈ 32% of US
price level, 2025
GDP per capita
$17,547
2025
Happiness
5.8 / 10
World Happiness, 2025
Safe drinking water
76%
of population, 2024
Homicide rate
6.8
per 100k, 2021
Road deaths
12
per 100k/yr, 2019
Income group
High
World Bank
English
Moderate
EF EPI 521
Religion
other Christian 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Irkutsk (52.2957°, 104.2908°, elevation 415 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).