Lahti climate — normals and trends
Lahti (Finland) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 4.3 °C and it receives 639 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (17.0 °C on average) and the coldest is January (-7.3 °C). Rainfall peaks in July.
Lahti averages 157 frost days, 0 hot days (≥ 30 °C) and 131 rainy days per year.
Lahti has warmed by +2.4 °C between 1940 and 2025, or +0.28 °C per decade. This trend is statistically significant.
The number of frost days there went from about 175 to 139 per year over the period.
The hottest day of the period reached 32.0 °C (on 28 July 2010) and the coldest -37.6 °C (on 10 January 1987).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
LahtiPaijat-Hame
- coords
- 60.98°, 25.66°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
4.3°C
Average daily high
7.4°C
Average daily low
1.2°C
Annual rainfall
639mm
Sunshine / day
7.0h
Mean relative humidity
81%
Average peak wind
15.7km/h
Seasonal range
24.3°C
Frost days (< 0 °C)
157 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
131 d/yr
Annual snowfall
136.8 cm
Average feels-like high
4.3 °C
Average feels-like low
-2.3 °C
Average peak gust
34.9 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
8.9 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.4 °C
since 1940
+0.3 °C per decade · r² = 0.35 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
32.0 °C
28 July 2010
Coldest day
-37.6 °C
10 January 1987
Wettest day
75 mm
12 August 1972
Windiest day
39.4 km/h
1 October 1994
Strongest gust
92.9 km/h
10 February 2020
Hottest feels-like
32.7 °C
28 July 2010
Coldest feels-like
-43.6 °C
10 January 1987
Snowiest day
16.0 cm
20 December 1970
Sunniest day
18.3 h
17 June 1940
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | -0.1 °C | +4.9 °C | 56 mm | +13 mm |
| Feb | -2.0 °C | +2.6 °C | 15 mm | -19 mm |
| Mar | 4.8 °C | +4.6 °C | 25 mm | -10 mm |
| Apr | 9.1 °C | +2.5 °C | 44 mm | +5 mm |
| May | 12.8 °C | -1.1 °C | 42 mm | -5 mm |
| Jun | 17.4 °C | -1.2 °C | 127 mm | +62 mm |
| Jul | 24.1 °C | +3.4 °C | 84 mm | +3 mm |
| Aug | 18.9 °C | -0.2 °C | 92 mm | +13 mm |
| Sep | 16.9 °C | +3.3 °C | 67 mm | +8 mm |
| Oct | 8.6 °C | +1.5 °C | 54 mm | -1 mm |
| Nov | 4.7 °C | +3.3 °C | 37 mm | -17 mm |
| Dec | 2.4 °C | +4.8 °C | 54 mm | +4 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Lahti?
Lahti has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 4.3 °C and it receives 639 mm of precipitation per year.
What is the hottest day ever recorded in Lahti?
The hottest day measured in Lahti between 1940 and 2025 was 28 July 2010, reaching 32.0 °C.
What is the coldest day in Lahti?
The coldest day measured in Lahti between 1940 and 2025 was 10 January 1987, at -37.6 °C.
Does it snow in Lahti?
Yes. Lahti gets on average 136.8 cm of snow per year and has around 157 frost days.
Has the climate of Lahti warmed?
Yes: Lahti warmed by +2.4 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Lahti?
The wettest day measured in Lahti between 1940 and 2025 was 12 August 1972, with 75 mm of rain in 24 hours.
What was the windiest day in Lahti?
The windiest day measured in Lahti between 1940 and 2025 was 1 October 1994, with winds reaching 39.4 km/h.
What is the warmest month in Lahti?
The warmest month in Lahti is July (17.0 °C on average); the coldest is January (-7.3 °C).
How much does it rain in Lahti?
Lahti receives on average 639 mm of precipitation per year, spread over about 131 rainy days.
Is it sunny in Lahti?
Lahti gets on average 7.0 hours of sunshine per day, roughly 2,555 hours per year over 1940-2025.
What is the biggest single-day snowfall in Lahti?
The heaviest 24-hour snowfall measured in Lahti between 1940 and 2025 was 20 December 1970, with 16.0 cm.
Are there tropical nights in Lahti?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Lahti.
What was the most extreme apparent temperature in Lahti?
In Lahti, between 1940 and 2025, the highest apparent temperature reached 32.7 °C on 28 July 2010, and the lowest was -43.6 °C on 10 January 1987.
Compare Lahti with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Lahti