Climate averages 1991–2020
Lahti weather
by month.
See how the year changes. July has the highest average daily maximum; March has the lowest average monthly precipitation.
Long-term climate patterns, not a forecast for a particular trip.
Across the year Lahti averages a daytime high of 8.0°C and a nighttime low of 2.1°C, with about 615 mm of precipitation on roughly 125 days. July is the warmest month (average high 21.2°C) and February the coolest (-3.7°C). July is the wettest month with 76 mm; March is the driest with 33 mm.
The annual picture
A year in Lahti
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
Lahti climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -3.6°C-8.0°C | -8.0°C | 41 | 10.3 | 6.57 h |
| February | -3.7°C-8.7°C | -8.7°C | 34 | 8.2 | 9.09 h |
| March | 0.7°C-5.7°C | -5.7°C | 33 | 8.4 | 11.712 h |
| April | 7.4°C-0.6°C | -0.6°C | 35 | 8.8 | 14.615 h |
| May | 14.5°C5.6°C | 5.6°C | 48 | 10.0 | 17.417 h |
| June | 18.6°C10.8°C | 10.8°C | 75 | 12.3 | 19.119 h |
| July | 21.2°C13.9°C | 13.9°C | 76 | 12.3 | 18.318 h |
| August | 19.6°C12.9°C | 12.9°C | 68 | 11.6 | 15.816 h |
| September | 14.1°C8.5°C | 8.5°C | 51 | 9.8 | 13.013 h |
| October | 7.0°C3.0°C | 3.0°C | 56 | 11.1 | 10.110 h |
| November | 1.8°C-1.3°C | -1.3°C | 50 | 10.8 | 7.47 h |
| December | -1.5°C-5.2°C | -5.2°C | 48 | 11.6 | 5.76 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
Nearby cities
- KouvolaFinland · 58 kmHigh 8.0°C · Low 2.0°C · 620 mm precipitation a year
- VantaaFinland · 84 kmHigh 8.8°C · Low 2.8°C · 661 mm precipitation a year
- HelsinkiFinland · 99 kmHigh 8.3°C · Low 3.3°C · 661 mm precipitation a year
- EspooFinland · 103 kmHigh 8.3°C · Low 3.5°C · 643 mm precipitation a year
- TampereFinland · 116 kmHigh 7.5°C · Low 2.3°C · 619 mm precipitation a year
- LappeenrantaFinland · 136 kmHigh 7.4°C · Low 2.0°C · 627 mm precipitation a year
- JyväskyläFinland · 140 kmHigh 7.1°C · Low 1.6°C · 623 mm precipitation a year
- VyborgRussia · 170 kmHigh 7.7°C · Low 2.4°C · 650 mm precipitation a year
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 limitsWhat do the high and low temperatures mean?
We average the daily maximum and daily minimum for each calendar month over 1991–2020. They are not record extremes, a forecast range or temperatures at a fixed time of day.
How is a rain day counted?
A local calendar day (standard time, UTC+2, no daylight saving) with at least 1 mm of total precipitation counts as one rain day. We count these for each year and month, then average across 30 years. The average does not predict which days will be wet.
Where do the numbers come from?
ERA5-Land (temperature) and ERA5 (precipitation) reanalysis from the Copernicus Climate Change Service, read from the Open-Meteo open-data archive. Temperature comes from the 0.1° model cell at 61.00°, 25.70° (3 km from the city centre). Rain comes from the 0.25° cell at 61.00°, 25.75°. These are model estimates, not weather-station readings; coast, hills and city streets can differ.
Does this page show sunshine, humidity or sea temperature?
No. The data used here contain air temperature and precipitation only. Daylight hours are calculated from the city's latitude (sunrise to sunset), not measured sunshine.