| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -3.3° | -8.8° | 40mm | 16.2 | 0 |
| February | -2.3° | -8.3° | 31.8mm | 12.9 | 4 |
| March | 2.4° | -5.5° | 28.7mm | 11.3 | 11 |
| April | 9.3° | -0.3° | 34.9mm | 10.9 | 41 |
| May | 16.5° | 5.4° | 34.5mm | 9.7 | 69 |
| June | 20.5° | 10° | 60.9mm | 11.2 | 78 |
| July | 23° | 13.3° | 65.1mm | 13.1 | 74 |
| August | 21.2° | 12° | 74.8mm | 12.9 | 74 |
| September | 15.6° | 7.9° | 52.7mm | 11.7 | 63 |
| October | 8.3° | 2.5° | 64.1mm | 14.6 | 33 |
| November | 3.2° | -0.7° | 51.7mm | 17.1 | 12 |
| December | -0.7° | -5.4° | 46.7mm | 16.7 | 4 |
January in Hämeenlinna averages a daily high of -3.3°C with nights around -8.8°C. Expect roughly 16.2 wet days totalling 40mm. A hard month to visit for comfort alone.
February in Hämeenlinna averages a daily high of -2.3°C with nights around -8.3°C. Expect roughly 12.9 wet days totalling 31.8mm. A hard month to visit for comfort alone.
March in Hämeenlinna averages a daily high of 2.4°C with nights around -5.5°C. Expect roughly 11.3 wet days totalling 28.7mm. A hard month to visit for comfort alone.
April in Hämeenlinna averages a daily high of 9.3°C with nights around -0.3°C. Expect roughly 10.9 wet days totalling 34.9mm. Demanding conditions — pack for it and plan indoor options.
May in Hämeenlinna averages a daily high of 16.5°C with nights around 5.4°C. Expect roughly 9.7 wet days totalling 34.5mm. Generally workable, with some weather to plan around.
June in Hämeenlinna averages a daily high of 20.5°C with nights around 10°C. Expect roughly 11.2 wet days totalling 60.9mm. Comfortable conditions for being outdoors all day.
July in Hämeenlinna averages a daily high of 23°C with nights around 13.3°C. Expect roughly 13.1 wet days totalling 65.1mm. Generally workable, with some weather to plan around.
August in Hämeenlinna averages a daily high of 21.2°C with nights around 12°C. Expect roughly 12.9 wet days totalling 74.8mm. Generally workable, with some weather to plan around.
September in Hämeenlinna averages a daily high of 15.6°C with nights around 7.9°C. Expect roughly 11.7 wet days totalling 52.7mm. Generally workable, with some weather to plan around.
October in Hämeenlinna averages a daily high of 8.3°C with nights around 2.5°C. Expect roughly 14.6 wet days totalling 64.1mm. A hard month to visit for comfort alone.
November in Hämeenlinna averages a daily high of 3.2°C with nights around -0.7°C. Expect roughly 17.1 wet days totalling 51.7mm. A hard month to visit for comfort alone.
December in Hämeenlinna averages a daily high of -0.7°C with nights around -5.4°C. Expect roughly 16.7 wet days totalling 46.7mm. 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. Hämeenlinna peaks at 78.
Based on 30 years of records, June–August scores highest for comfort in Hämeenlinna, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 23°C.
August is the wettest, averaging 74.8mm of rain across roughly 12.9 wet days.
January is the coolest month, with average daily highs around -3.3°C.