At the HelsinkiKaisaniemi weather station, which we use for Helsinki, the warmest month is July (average high 21.9 °C) and the coldest February (average low −6.3 °C), averaged over 1991–2020. The wettest month is August (81 mm of rain). Finland's quietest month for visitors in 2025 was April.
Helsinki weather by month
Averages for 1991–2020 at the HelsinkiKaisaniemi weather station, copied from our Finland page, next to each month's share of Finland's tourist nights (Eurostat, 2025). These are long-term averages, not a forecast.
| Month | Average high | Average low | Rain | Rainy days | Daylight on the 15th | Share of 2025 |
|---|---|---|---|---|---|---|
| January | −0.7 °C | −5.6 °C | 53 mm | 11.5 days | 6 h 40 min | 6.9% |
| February | −1.3 °C | −6.3 °C | 38 mm | 8.8 days | 9 h 10 min | 7.9% |
| March | 2.3 °C | −3.6 °C | 34 mm | 7.6 days | 11 h 45 min | 7.8% |
| April | 8.1 °C | 1.1 °C | 34 mm | 7.3 days | 14 h 35 min | 6.3% |
| May | 14.6 °C | 6.4 °C | 38 mm | 6.8 days | 17 h 10 min | 6.9% |
| June | 18.8 °C | 11.2 °C | 60 mm | 8.4 days | 18 h 55 min | 10.0% |
| July | 21.9 °C | 14.5 °C | 57 mm | 7.4 days | 18 h 5 min | 14.0% |
| August | 20.5 °C | 13.5 °C | 81 mm | 9.7 days | 15 h 40 min | 10.1% |
| September | 15.4 °C | 9.3 °C | 56 mm | 8.6 days | 12 h 55 min | 7.8% |
| October | 9.2 °C | 4.2 °C | 73 mm | 10.2 days | 10 h 10 min | 7.3% |
| November | 4.4 °C | 0.4 °C | 69 mm | 11.5 days | 7 h 30 min | 6.7% |
| December | 1.4 °C | −2.9 °C | 58 mm | 11.3 days | 5 h 50 min | 8.3% |
Golden hour and sea temperature
Evening golden hour is our calculation for the 15th of each month of 2026: the time the sun takes to go from 6° above to 4° below the horizon (there is no official definition). The sea figure is the 1991–2020 average sea surface temperature at the open-sea point nearest the weather station (NOAA OISST).
| Month | Evening golden hour (15th) | Sea surface |
|---|---|---|
| January | 2 h 10 min | 2.1 °C |
| February | 1 h 32 min | 0.8 °C |
| March | 1 h 21 min | 0.7 °C |
| April | 1 h 25 min | 2.2 °C |
| May | 1 h 45 min | 6.2 °C |
| June | 2 h 13 min | 11.4 °C |
| July | 1 h 57 min | 16.1 °C |
| August | 1 h 31 min | 17.2 °C |
| September | 1 h 21 min | 14.4 °C |
| October | 1 h 26 min | 10.3 °C |
| November | 1 h 51 min | 7.0 °C |
| December | 2 h 46 min | 4.2 °C |
The quietest and busiest months
In 2025, April was Finland's quietest month (6.3% of the year's tourist nights): average high 8.1 °C, average low 1.1 °C, 34 mm of rain. July was the busiest (14.0%): average high 21.9 °C, average low 14.5 °C, 57 mm of rain. The figures do not show that the weather makes a month busier or quieter, so we do not say it does.
What these figures are
One weather station stands for Helsinki; places nearby can differ, especially by height or distance from the sea. For the full picture of Finland, including regions and holidays, see our Finland page; for other places, the visual guides and golden hour by place.
Key takeaways
- Warmest month: July (average high 21.9 °C); coldest: February (average low −6.3 °C).
- Wettest month: August (81 mm); driest: March and April (34 mm).
- In 2025, April was Finland's quietest month for visitors and July the busiest.
Sources
Weather normals and daylight copied from our country or prefecture page; tourism shares from the same page. See how we research.
- Weather: WMO Member Nations (2023). WMO Climatological Standard Normals for 1991-2020 (NCEI Accession 0253808), station HelsinkiKaisaniemi (station ID 00002978), mean daily maximum and minimum temperature, precipitation and number of days with at least 1 mm of precipitation, normals computed from at least 24 years. NOAA National Centers for Environmental Information. Dataset. doi:10.25921/800j-vn07. Accessed 22 September 2026. Released by NOAA under CC0.
- Daylight: our calculation of the time from sunrise to sunset on the 15th of each month of 2026 at the weather station's location, by the method of the NOAA Solar Calculator (NOAA Global Monitoring Laboratory, “Solar Calculation Details”, based on Jean Meeus, Astronomical Algorithms, allowing 0.833° for refraction and the size of the sun). Read it. Checked 22 September 2026. NOAA notes that calculated times can differ from what is observed.
- Source: Eurostat, Nights spent at tourist accommodation establishments – monthly data, doi:10.2908/TOUR_OCC_NIM, accessed 25 September 2026. Dataset last updated by Eurostat on 22 September 2026. Extract: number of nights, NACE codes I55.1–I55.3, all guests and split by guests resident in the country and abroad, January–December 2025.
- Sea temperature: NOAA Optimum Interpolation Sea Surface Temperature (OISST) v2.1, 0.25° grid, monthly long-term mean 1991–2020 (file sst.mon.ltm.1991-2020.nc). Data provided by the NOAA/OAR/PSL, Boulder, Colorado, USA, from their Web site at https://psl.noaa.gov/. Huang, B., C. Liu, V. Banzon, E. Freeman, G. Graham, B. Hankins, T. Smith and H.-M. Zhang (2021), Improvements of the Daily Optimum Interpolation Sea Surface Temperature (DOISST) Version 2.1, Journal of Climate 34, 2923–2939, doi:10.1175/JCLI-D-20-0166.1. Dataset page. Accessed 24 September 2026. Public domain (NOAA PSL disclaimer). The choice of grid cell and the rounding are ours; these are not official NOAA figures, and NOAA does not endorse this site.
Modified data: the arrangement, the golden-hour and sea columns and the quietest/busiest comparison are ours, from the cited figures.