| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -13.1° | -21.8° | 16.2mm | 11.4 | 7 |
| February | -7.6° | -19.3° | 10mm | 7.1 | 16 |
| March | 1.1° | -11.4° | 11.7mm | 6.8 | 16 |
| April | 10.5° | -1.9° | 23.5mm | 7.2 | 49 |
| May | 18.1° | 3.7° | 37.2mm | 9.8 | 74 |
| June | 23.9° | 10.2° | 67.2mm | 11.8 | 76 |
| July | 25.6° | 13.5° | 109.2mm | 14 | 72 |
| August | 22.9° | 11.3° | 88.6mm | 11.7 | 77 |
| September | 16.2° | 4.5° | 46.9mm | 10.6 | 67 |
| October | 7.8° | -2.4° | 21.1mm | 8.1 | 38 |
| November | -3° | -11.6° | 18.4mm | 10.2 | 10 |
| December | -10.7° | -18.9° | 19.1mm | 12.6 | 5 |
January in Irkutsk averages a daily high of -13.1°C with nights around -21.8°C. Expect roughly 11.4 wet days totalling 16.2mm. A hard month to visit for comfort alone.
February in Irkutsk averages a daily high of -7.6°C with nights around -19.3°C. Expect roughly 7.1 wet days totalling 10mm. A hard month to visit for comfort alone.
March in Irkutsk averages a daily high of 1.1°C with nights around -11.4°C. Expect roughly 6.8 wet days totalling 11.7mm. A hard month to visit for comfort alone.
April in Irkutsk averages a daily high of 10.5°C with nights around -1.9°C. Expect roughly 7.2 wet days totalling 23.5mm. Demanding conditions — pack for it and plan indoor options.
May in Irkutsk averages a daily high of 18.1°C with nights around 3.7°C. Expect roughly 9.8 wet days totalling 37.2mm. Generally workable, with some weather to plan around.
June in Irkutsk averages a daily high of 23.9°C with nights around 10.2°C. Expect roughly 11.8 wet days totalling 67.2mm. Comfortable conditions for being outdoors all day.
July in Irkutsk averages a daily high of 25.6°C with nights around 13.5°C. Expect roughly 14 wet days totalling 109.2mm. Generally workable, with some weather to plan around.
August in Irkutsk averages a daily high of 22.9°C with nights around 11.3°C. Expect roughly 11.7 wet days totalling 88.6mm. Comfortable conditions for being outdoors all day.
September in Irkutsk averages a daily high of 16.2°C with nights around 4.5°C. Expect roughly 10.6 wet days totalling 46.9mm. Generally workable, with some weather to plan around.
October in Irkutsk averages a daily high of 7.8°C with nights around -2.4°C. Expect roughly 8.1 wet days totalling 21.1mm. Demanding conditions — pack for it and plan indoor options.
November in Irkutsk averages a daily high of -3°C with nights around -11.6°C. Expect roughly 10.2 wet days totalling 18.4mm. A hard month to visit for comfort alone.
December in Irkutsk averages a daily high of -10.7°C with nights around -18.9°C. Expect roughly 12.6 wet days totalling 19.1mm. A hard month to visit for comfort alone.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Irkutsk peaks at 77.
Based on 30 years of records, May–August scores highest for comfort in Irkutsk, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 25.6°C.
July is the wettest, averaging 109.2mm of rain across roughly 14 wet days.
January is the coolest month, with average daily highs around -13.1°C.