| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -1.4° | -5.8° | — | — | 27 |
| February | -1.7° | -6.1° | — | — | 27 |
| March | 1.3° | -3.6° | — | — | 31 |
| April | 6.7° | 1° | — | — | 50 |
| May | 12.9° | 6.6° | — | — | 71 |
| June | 17.6° | 11.7° | — | — | 86 |
| July | 21.1° | 15.4° | — | — | 94 |
| August | 20° | 14.8° | — | — | 94 |
| September | 15.4° | 10.8° | — | — | 79 |
| October | 9.3° | 5.5° | — | — | 60 |
| November | 4.8° | 1.4° | — | — | 44 |
| December | 1.2° | -2.6° | — | — | 32 |
January in Porvoo averages a daily high of -1.4°C with nights around -5.8°C. A hard month to visit for comfort alone.
February in Porvoo averages a daily high of -1.7°C with nights around -6.1°C. A hard month to visit for comfort alone.
March in Porvoo averages a daily high of 1.3°C with nights around -3.6°C. A hard month to visit for comfort alone.
April in Porvoo averages a daily high of 6.7°C with nights around 1°C. Demanding conditions — pack for it and plan indoor options.
May in Porvoo averages a daily high of 12.9°C with nights around 6.6°C. Generally workable, with some weather to plan around.
June in Porvoo averages a daily high of 17.6°C with nights around 11.7°C. Comfortable conditions for being outdoors all day.
July in Porvoo averages a daily high of 21.1°C with nights around 15.4°C. Comfortable conditions for being outdoors all day.
August in Porvoo averages a daily high of 20°C with nights around 14.8°C. Comfortable conditions for being outdoors all day.
September in Porvoo averages a daily high of 15.4°C with nights around 10.8°C. Comfortable conditions for being outdoors all day.
October in Porvoo averages a daily high of 9.3°C with nights around 5.5°C. Generally workable, with some weather to plan around.
November in Porvoo averages a daily high of 4.8°C with nights around 1.4°C. Demanding conditions — pack for it and plan indoor options.
December in Porvoo averages a daily high of 1.2°C with nights around -2.6°C. 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. Porvoo peaks at 94.
Based on 30 years of records, June–August scores highest for comfort in Porvoo, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 21.1°C.
January is the wettest, averaging —mm of rain across roughly — wet days.
February is the coolest month, with average daily highs around -1.7°C.