Climate averages 1991–2020
Helsinki weather
in May.
A cool, moderately wet month: the 5th warmest and the 4th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a cool month in Helsinki: daytime highs average 13.1°C and nights cool to about 6.0°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 44 mm of rain on roughly 9 days, which makes May a moderately wet month (the 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 17 h 09 min on an average May day.
The nearest other city in this atlas is Vantaa (15 km away). In May its highs average 14.8°C, 1.7°C warmer than Helsinki, with 44 mm of rain.
Among the 13 cities listed in Finland, Helsinki ranks 8th of 13 for the warmest May highs and joint 4th of 13 for the driest May (rainfall, lowest first). The mean May high of those 13 cities is 13.2°C; Helsinki is 0.1°C cooler than that mean.
From May to June, average highs rise by 4.2°C to 17.3°C, and monthly rainfall rises from 44 mm to 72 mm.
The annual picture
May in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Helsinki climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -2.1°C-6.0°C | -6.0°C | 48 | 10.9 | 6.87 h |
| February | -2.9°C-7.1°C | -7.1°C | 41 | 9.3 | 9.19 h |
| March | 0.7°C-4.6°C | -4.6°C | 37 | 8.5 | 11.712 h |
| April | 6.9°C0.3°C | 0.3°C | 37 | 8.7 | 14.515 h |
| May, selected | 13.1°C6.0°C | 6.0°C | 44 | 8.9 | 17.217 h |
| June | 17.3°C10.8°C | 10.8°C | 72 | 11.7 | 18.819 h |
| July | 20.8°C14.6°C | 14.6°C | 76 | 11.9 | 18.118 h |
| August | 19.6°C13.9°C | 13.9°C | 76 | 12.3 | 15.716 h |
| September | 14.6°C9.8°C | 9.8°C | 57 | 10.4 | 13.013 h |
| October | 8.1°C4.4°C | 4.4°C | 59 | 11.1 | 10.210 h |
| November | 3.3°C0.3°C | 0.3°C | 59 | 11.5 | 7.68 h |
| December | 0.1°C-3.2°C | -3.2°C | 55 | 12.2 | 6.06 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
May in nearby cities
- Vantaa in MayFinland · 15 kmHigh 14.8°C · Low 5.9°C · 44 mm rain
- Espoo in MayFinland · 16 kmHigh 12.9°C · Low 6.2°C · 43 mm rain
- Tallinn in MayEstonia · 82 kmHigh 14.6°C · Low 6.1°C · 41 mm rain
- Lahti in MayFinland · 99 kmHigh 14.5°C · Low 5.6°C · 48 mm rain
- Kouvola in MayFinland · 124 kmHigh 14.7°C · Low 5.8°C · 46 mm rain
- Turku in MayFinland · 150 kmHigh 14.4°C · Low 5.4°C · 41 mm rain
- Tampere in MayFinland · 160 kmHigh 13.2°C · Low 5.2°C · 45 mm rain
- Lappeenranta in MayFinland · 203 kmHigh 14.0°C · Low 5.2°C · 46 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Helsinki) is explained once on the Helsinki year overview and on the Sources, method and limits page.
Vantaa lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.