, with cold winters, during which the average temperature is a few degrees below freezing, and mild to pleasantly warm summers.
Hanko (Hangö in Swedish) is located in the south-western tip of Finland, in the area where the climate is (relatively) milder.
, when it doesn't get completely dark even at midnight, occur from May 13th to July 31st.
, there can be cold spells of arctic origin. The coldest record is -35.2 °C (-31.4 °F) and was set in February 1966.
, there can be short hot periods. The highest record is 31.1 °C (88 °F) and was set in July 1983.
, from June to August, since it is the mildest season. However, you must take into account some rainy days and a bit of cold at night.
. Here are the average temperatures.
January is generally a very cold month. The average temperature is of
-2.2 °C, with a minimum of
-4.5 °C and a maximum of
0 °C.

On the coldest nights of the month, the temperature usually drops to around
-15.5 °C. However, it dropped to
-26.3 °C in January 2003.

On the warmest days of the month, the temperature usually reaches around
4.5 °C. However, it reached
7.7 °C in January 2020.

Precipitation amounts to
55 mm, distributed over 11 days.
The day lasts on average 6 hours and 55 minutes. So the days are short.
The average humidity is 87%. Hence, the air is normally humid.
The average wind speed is of
20 kph.

The average sea temperature is of
2.9 °C. Therefore, the sea is very cold for swimming.
February, the coldest month of the year, is generally a very cold month. The average temperature is of
-3.2 °C, with a minimum of
-5.6 °C and a maximum of
-0.8 °C.

On the coldest nights of the month, the temperature usually drops to around
-15.5 °C. However, it dropped to
-24.5 °C in February 2001.

On the warmest days of the month, the temperature usually reaches around
4.5 °C. However, it reached
8.5 °C in February 2015.

Precipitation amounts to
40 mm, distributed over 9 days.
The day lasts on average 9 hours and 10 minutes.
The average humidity is 88%. Hence, the air is normally humid.
The average wind speed is of
18 kph.

The average sea temperature is of
1.6 °C. Therefore, the sea is very cold for swimming.
March is generally a very cold month. The average temperature is of
-0.8 °C, with a minimum of
-3.5 °C and a maximum of
2 °C.

On the coldest nights of the month, the temperature usually drops to around
-12 °C. However, it dropped to
-22 °C in March 2013.

On the warmest days of the month, the temperature usually reaches around
7.5 °C. However, it reached
14.4 °C in March 2007.

Precipitation amounts to
35 mm, distributed over 8 days.
The day lasts on average 11 hours and 55 minutes.
The average humidity is 86%. Hence, the air is normally humid.
The average wind speed is of
18 kph.

The average sea temperature is of
1.4 °C. Therefore, the sea is very cold for swimming.
April is generally a cold month. The average temperature is of
3.8 °C, with a minimum of
0.7 °C and a maximum of
6.8 °C.

On the coldest nights of the month, the temperature usually drops to around
-4 °C. However, it dropped to
-9.6 °C in April 2013.

On the warmest days of the month, the temperature usually reaches around
14 °C. However, it reached
19.7 °C in April 2014.

Precipitation amounts to
30 mm, distributed over 7 days.
The day lasts on average 14 hours and 40 minutes.
The average humidity is 82%. Hence, the air is normally humid.
The average wind speed is of
16 kph.

The average sea temperature is of
2.6 °C. Therefore, the sea is very cold for swimming.
May is generally a mild month. The average temperature is of
9.4 °C, with a minimum of
5.8 °C and a maximum of
13.1 °C.

On the coldest nights of the month, the temperature usually drops to around
0.5 °C. However, it dropped to
-1.9 °C in May 1999.

On the warmest days of the month, the temperature usually reaches around
21 °C. However, it reached
25.5 °C in May 1992.

Precipitation amounts to
35 mm, distributed over 6 days.
The day lasts on average 17 hours and 10 minutes. So the days are very long.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is of
16 kph.

The average sea temperature is of
5.7 °C. Therefore, the sea is very cold for swimming.
June is generally a mild month. The average temperature is of
14 °C, with a minimum of
10.5 °C and a maximum of
17.5 °C.

On the coldest nights of the month, the temperature usually drops to around
6 °C. However, it dropped to
3.3 °C in June 2009.

On the warmest days of the month, the temperature usually reaches around
23.5 °C. However, it reached
27.6 °C in June 2009.

Precipitation amounts to
50 mm, distributed over 8 days.
The day lasts on average 18 hours and 40 minutes. So the days are very long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
The average humidity is 76%. Hence, the air is normally humid.
The average wind speed is of
16 kph.

The average sea temperature is of
11 °C. Therefore, the sea is very cold for swimming.
July, the warmest month of the year, is generally a very mild month. The average temperature is of
17.7 °C, with a minimum of
14.3 °C and a maximum of
21.1 °C.

On the coldest nights of the month, the temperature usually drops to around
10 °C. However, it dropped to
7.9 °C in July 1992.

On the warmest days of the month, the temperature usually reaches around
26 °C. However, it reached
30.9 °C in July 2019.

Precipitation amounts to
50 mm, distributed over 7 days.
The day lasts on average 17 hours and 50 minutes. So the days are very long.
The average humidity is 80%. Hence, the air is normally humid.
The average wind speed is of
15 kph.

The average sea temperature is of
16.2 °C. Therefore, the sea is cold for swimming.
August is generally a very mild month. The average temperature is of
16.9 °C, with a minimum of
13.9 °C and a maximum of
20 °C.

On the coldest nights of the month, the temperature usually drops to around
9 °C. However, it dropped to
5.4 °C in August 2007.

On the warmest days of the month, the temperature usually reaches around
24.5 °C. However, it reached
28 °C in August 2018.

Precipitation amounts to
80 mm, distributed over 9 days.
The day lasts on average 15 hours and 30 minutes. So the days are long.
The average humidity is 82%. Hence, the air is normally humid.
The average wind speed is of
15 kph.

The average sea temperature is of
17.4 °C. Therefore, the sea is cold for swimming.
September is generally a mild month. The average temperature is of
12.6 °C, with a minimum of
10 °C and a maximum of
15.2 °C.

On the coldest nights of the month, the temperature usually drops to around
4 °C. However, it dropped to
0.8 °C in September 2013.

On the warmest days of the month, the temperature usually reaches around
19.5 °C. However, it reached
23.2 °C in September 2002.

Precipitation amounts to
50 mm, distributed over 9 days.
The day lasts on average 12 hours and 50 minutes.
The average humidity is 83%. Hence, the air is normally humid.
The average wind speed is of
18 kph.

The average sea temperature is of
14.6 °C. Therefore, the sea is very cold for swimming.
October is generally a quite mild month. The average temperature is of
7.2 °C, with a minimum of
5 °C and a maximum of
9.3 °C.

On the coldest nights of the month, the temperature usually drops to around
-2 °C. However, it dropped to
-9.2 °C in October 1992.

On the warmest days of the month, the temperature usually reaches around
14 °C. However, it reached
16.1 °C in October 2011.

Precipitation amounts to
75 mm, distributed over 11 days.
The day lasts on average 10 hours and 0 minutes.
The average humidity is 85%. Hence, the air is normally humid.
The average wind speed is of
19 kph.

The average sea temperature is of
10.8 °C. Therefore, the sea is very cold for swimming.
November is generally a cold month. The average temperature is of
3.1 °C, with a minimum of
1.2 °C and a maximum of
4.9 °C.

On the coldest nights of the month, the temperature usually drops to around
-6 °C. However, it dropped to
-13.7 °C in November 2010.

On the warmest days of the month, the temperature usually reaches around
9.5 °C. However, it reached
12.2 °C in November 2015.

Precipitation amounts to
70 mm, distributed over 12 days.
The day lasts on average 7 hours and 30 minutes. So the days are short.
The average humidity is 86%. Hence, the air is normally humid.
The average wind speed is of
21 kph.

The average sea temperature is of
7.5 °C. Therefore, the sea is very cold for swimming.
December is generally a cold month. The average temperature is of
0.1 °C, with a minimum of
-2 °C and a maximum of
2.2 °C.

On the coldest nights of the month, the temperature usually drops to around
-10.5 °C. However, it dropped to
-22.4 °C in December 2002.

On the warmest days of the month, the temperature usually reaches around
6 °C. However, it reached
9.5 °C in December 2011.

Precipitation amounts to
60 mm, distributed over 13 days.
The day lasts on average 6 hours and 5 minutes. So the days are short. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
The average humidity is 88%. Hence, the air is normally humid.
The average wind speed is of
21 kph.

The average sea temperature is of
4.9 °C. Therefore, the sea is very cold for swimming.