| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -2.9° | -9.4° | 31.9mm | 14.5 | 1 |
| February | -2.5° | -9.9° | 26.7mm | 11.7 | 7 |
| March | 1.8° | -6.9° | 25.4mm | 9.8 | 12 |
| April | 8.3° | -1.3° | 30.1mm | 9.3 | 39 |
| May | 15.1° | 3.3° | 48.9mm | 10.1 | 64 |
| June | 20° | 8.5° | 55.2mm | 10.6 | 79 |
| July | 22.3° | 11.3° | 78.1mm | 13 | 74 |
| August | 20.7° | 9.9° | 81.6mm | 13.1 | 74 |
| September | 15.3° | 5.9° | 52.2mm | 11.7 | 62 |
| October | 7.9° | 1.7° | 59.3mm | 14.9 | 31 |
| November | 2.2° | -2.4° | 48.2mm | 15.4 | 8 |
| December | -1.3° | -7° | 39.5mm | 15.5 | 2 |
January in Seinäjoki averages a daily high of -2.9°C with nights around -9.4°C. Expect roughly 14.5 wet days totalling 31.9mm. A hard month to visit for comfort alone.
February in Seinäjoki averages a daily high of -2.5°C with nights around -9.9°C. Expect roughly 11.7 wet days totalling 26.7mm. A hard month to visit for comfort alone.
March in Seinäjoki averages a daily high of 1.8°C with nights around -6.9°C. Expect roughly 9.8 wet days totalling 25.4mm. A hard month to visit for comfort alone.
April in Seinäjoki averages a daily high of 8.3°C with nights around -1.3°C. Expect roughly 9.3 wet days totalling 30.1mm. Demanding conditions — pack for it and plan indoor options.
May in Seinäjoki averages a daily high of 15.1°C with nights around 3.3°C. Expect roughly 10.1 wet days totalling 48.9mm. Generally workable, with some weather to plan around.
June in Seinäjoki averages a daily high of 20°C with nights around 8.5°C. Expect roughly 10.6 wet days totalling 55.2mm. Comfortable conditions for being outdoors all day.
July in Seinäjoki averages a daily high of 22.3°C with nights around 11.3°C. Expect roughly 13 wet days totalling 78.1mm. Generally workable, with some weather to plan around.
August in Seinäjoki averages a daily high of 20.7°C with nights around 9.9°C. Expect roughly 13.1 wet days totalling 81.6mm. Generally workable, with some weather to plan around.
September in Seinäjoki averages a daily high of 15.3°C with nights around 5.9°C. Expect roughly 11.7 wet days totalling 52.2mm. Generally workable, with some weather to plan around.
October in Seinäjoki averages a daily high of 7.9°C with nights around 1.7°C. Expect roughly 14.9 wet days totalling 59.3mm. A hard month to visit for comfort alone.
November in Seinäjoki averages a daily high of 2.2°C with nights around -2.4°C. Expect roughly 15.4 wet days totalling 48.2mm. A hard month to visit for comfort alone.
December in Seinäjoki averages a daily high of -1.3°C with nights around -7°C. Expect roughly 15.5 wet days totalling 39.5mm. 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. Seinäjoki peaks at 79.
Based on 30 years of records, June–August scores highest for comfort in Seinäjoki, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 22.3°C.
August is the wettest, averaging 81.6mm of rain across roughly 13.1 wet days.
January is the coolest month, with average daily highs around -2.9°C.