| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -6.4° | -12.3° | 38.7mm | 18.9 | 0 |
| February | -4.9° | -11.4° | 29.4mm | 13.5 | 3 |
| March | 0.9° | -6.5° | 29.9mm | 11.8 | 9 |
| April | 10.2° | 0.8° | 33.8mm | 10.7 | 45 |
| May | 18.4° | 7.2° | 51.8mm | 11.6 | 72 |
| June | 21.8° | 11.1° | 75.9mm | 13 | 74 |
| July | 24.7° | 14° | 72.8mm | 11.5 | 77 |
| August | 22.2° | 11.9° | 73.7mm | 12 | 76 |
| September | 15.7° | 7.2° | 58mm | 11.9 | 62 |
| October | 7.6° | 1.9° | 63.1mm | 15.5 | 30 |
| November | 0.3° | -4.1° | 50.3mm | 15 | 6 |
| December | -4.1° | -9.3° | 39.7mm | 17.1 | 0 |
January in Kostroma averages a daily high of -6.4°C with nights around -12.3°C. Expect roughly 18.9 wet days totalling 38.7mm. A hard month to visit for comfort alone.
February in Kostroma averages a daily high of -4.9°C with nights around -11.4°C. Expect roughly 13.5 wet days totalling 29.4mm. A hard month to visit for comfort alone.
March in Kostroma averages a daily high of 0.9°C with nights around -6.5°C. Expect roughly 11.8 wet days totalling 29.9mm. A hard month to visit for comfort alone.
April in Kostroma averages a daily high of 10.2°C with nights around 0.8°C. Expect roughly 10.7 wet days totalling 33.8mm. Demanding conditions — pack for it and plan indoor options.
May in Kostroma averages a daily high of 18.4°C with nights around 7.2°C. Expect roughly 11.6 wet days totalling 51.8mm. Generally workable, with some weather to plan around.
June in Kostroma averages a daily high of 21.8°C with nights around 11.1°C. Expect roughly 13 wet days totalling 75.9mm. Generally workable, with some weather to plan around.
July in Kostroma averages a daily high of 24.7°C with nights around 14°C. Expect roughly 11.5 wet days totalling 72.8mm. Comfortable conditions for being outdoors all day.
August in Kostroma averages a daily high of 22.2°C with nights around 11.9°C. Expect roughly 12 wet days totalling 73.7mm. Comfortable conditions for being outdoors all day.
September in Kostroma averages a daily high of 15.7°C with nights around 7.2°C. Expect roughly 11.9 wet days totalling 58mm. Generally workable, with some weather to plan around.
October in Kostroma averages a daily high of 7.6°C with nights around 1.9°C. Expect roughly 15.5 wet days totalling 63.1mm. A hard month to visit for comfort alone.
November in Kostroma averages a daily high of 0.3°C with nights around -4.1°C. Expect roughly 15 wet days totalling 50.3mm. A hard month to visit for comfort alone.
December in Kostroma averages a daily high of -4.1°C with nights around -9.3°C. Expect roughly 17.1 wet days totalling 39.7mm. 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. Kostroma peaks at 77.
Based on 30 years of records, May–August scores highest for comfort in Kostroma, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 24.7°C.
June is the wettest, averaging 75.9mm of rain across roughly 13 wet days.
January is the coolest month, with average daily highs around -6.4°C.