Climate - Oulu (Finland)

The climate of Oulu is cold continental, with freezing winters and mild summers.
The city is located in north-central Finland, in the northernmost part of the Gulf of Bothnia (called Perämeri), which can freeze in winter. It is useful to recall that sea water freezes at about -2 °C (28.5 °F).
We are at the 65th parallel, therefore south of the Polar Circle. The white nights, when it doesn't get completely dark even at midnight, occur from April 25th to August 18th.
In winter, there can be cold spells of arctic origin. The coldest record is -41.5 °C (-42.7 °F) and was set in February 1966.
In summer, there can be short hot periods. The highest record is 33.2 °C (91.8 °F) and was set in July 2018.

Best Time

The best time to visit Oulu is the summer, 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.

Oulu - Climate data

In Oulu, the average temperature of the coldest month (February) is of -8.7 °C (16.4 °F), that of the warmest month (July) is of 16.7 °C (62.1 °F). Here are the average temperatures.
In Oulu, precipitation amounts to 520 millimeters (20.5 inches) per year: so, it is at an intermediate level. It ranges from 25 mm (1 in) in the driest months (March, April) to 75 mm (3 in) in the wettest one (July). Here is the average precipitation.
At Oulu, the sea temperature ranges from -0.5 °C (31 °F) in February, March to 13.5 °C (56 °F) in August. Here are the average sea temperatures.
In Oulu, there are on average around 1740 sunshine hours per year. Here are the average hours of sunshine per day.

Oulu - Weather by month

Based on the period 1991-2020

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In January, the weather in Oulu is usually freezing cold. The average temperature is of -8.4 °C (17 °F), with a minimum of -12 °C (10.5 °F) and a maximum of -4.9 °C (23.2 °F).
On the coldest nights of the month, the temperature usually drops to around -26.5 °C (-15.5 °F). However, it dropped to -36.6 °C (-33.9 °F) in January 1999.
On the warmest days of the month, the temperature usually reaches around 3.5 °C (38 °F). However, it reached 7.2 °C (45 °F) in January 2002.
Precipitation amounts to 30 mm (1.2 in), distributed over 9 days.
The day lasts on average 5 hours and 10 minutes. So the days are short.
There is an average of 1 hour of sunshine per day. So, the sun shines 15% of the time.
The average humidity is 88%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 0.5 °C (33.5 °F). Therefore, the sea is very cold for swimming.

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In February, the coldest month of the year, the weather in Oulu is usually freezing cold. The average temperature is of -8.7 °C (16 °F), with a minimum of -12.4 °C (9.6 °F) and a maximum of -4.9 °C (23.2 °F).
On the coldest nights of the month, the temperature usually drops to around -25.5 °C (-14.5 °F). However, it dropped to -34.3 °C (-29.7 °F) in February 2011.
On the warmest days of the month, the temperature usually reaches around 3.5 °C (38.5 °F). However, it reached 6.3 °C (43.3 °F) in February 2017.
Precipitation amounts to 30 mm (1.2 in), distributed over 8 days.
The day lasts on average 8 hours and 30 minutes.
There are on average 2.5 hours of sunshine per day. So, the sun shines 29% of the time.
The average humidity is 86%. Hence, the air is normally humid.
The average wind speed is 12 kph (8 mph).
The average sea temperature is of -0.5 °C (31.5 °F). Therefore, the sea is very cold for swimming.

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In March, the weather in Oulu is usually very cold. The average temperature is of -4.4 °C (24 °F), with a minimum of -8.5 °C (16.7 °F) and a maximum of -0.2 °C (31.6 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -20.5 °C (-4.5 °F). However, it dropped to -28.3 °C (-18.9 °F) in March 2010.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 6.5 °C (44 °F). However, it reached 11.5 °C (52.7 °F) in March 2016.
Precipitation amounts to 25 mm (1 in), distributed over 7 days.
The day lasts on average 11 hours and 55 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 37% of the time.
The average humidity is 80%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of -0.5 °C (30.5 °F). Therefore, the sea is very cold for swimming.

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In April, the weather in Oulu is usually cold. The average temperature is of 1.7 °C (35 °F), with a minimum of -2.6 °C (27.4 °F) and a maximum of 6 °C (42.8 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -11 °C (12 °F). However, it dropped to -19.2 °C (-2.6 °F) in April 1997.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 15 °C (59 °F). However, it reached 20.3 °C (68.5 °F) in April 1999.
Precipitation amounts to 25 mm (1 in), distributed over 6 days.
The day lasts on average 15 hours and 25 minutes.
There are on average 7 hours of sunshine per day. So, the sun shines 45% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 12 kph (8 mph).
The average sea temperature is of 0 °C (32 °F). Therefore, the sea is very cold for swimming.

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In May, the weather in Oulu is usually quite mild. The average temperature is of 8.0 °C (46 °F), with a minimum of 3.2 °C (37.7 °F) and a maximum of 12.9 °C (55.2 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -3 °C (26 °F). However, it dropped to -6.7 °C (19.9 °F) in May 2007.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 23 °C (74 °F). However, it reached 29.9 °C (85.8 °F) in May 2014.
Precipitation amounts to 40 mm (1.6 in), distributed over 8 days.
The day lasts on average 19 hours and 0 minutes. So the days are very long.
There are on average 9 hours of sunshine per day. So, the sun shines 46% of the time.
The average humidity is 65%.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 2.5 °C (36 °F). Therefore, the sea is very cold for swimming.

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In June, the weather in Oulu is usually mild. The average temperature is of 13.4 °C (56 °F), with a minimum of 8.8 °C (47.9 °F) and a maximum of 18 °C (64.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 2.5 °C (36 °F). However, it dropped to -1 °C (30.2 °F) in June 2009.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 26 °C (79 °F). However, it reached 32.3 °C (90.1 °F) in June 2019.
Precipitation amounts to 50 mm (2 in), distributed over 8 days.
The day lasts on average 21 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.
There are on average 10 hours of sunshine per day. So, the sun shines 46% of the time.
The average humidity is 65%.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 7 °C (44 °F). Therefore, the sea is very cold for swimming.

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In July, the warmest month of the year, the weather in Oulu is usually very mild. The average temperature is of 16.7 °C (62 °F), with a minimum of 12.1 °C (53.8 °F) and a maximum of 21.3 °C (70.4 °F).
On the coldest nights of the month, the temperature usually drops to around 6.5 °C (44 °F). However, it dropped to 3.6 °C (38.5 °F) in July 2017.
On the warmest days of the month, the temperature usually reaches around 28 °C (82 °F). However, it reached 33.2 °C (91.8 °F) in July 2018.
Precipitation amounts to 75 mm (3 in), distributed over 10 days.
The day lasts on average 20 hours and 0 minutes. So the days are very long.
There are on average 9 hours of sunshine per day. So, the sun shines 46% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 12 °C (53.5 °F). Therefore, the sea is very cold for swimming.

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In August, the weather in Oulu is usually very mild. The average temperature is of 14.6 °C (58 °F), with a minimum of 10.2 °C (50.4 °F) and a maximum of 19 °C (66.3 °F).
On the coldest nights of the month, the temperature usually drops to around 3.5 °C (38 °F). However, it dropped to 0.3 °C (32.5 °F) in August 2019.
On the warmest days of the month, the temperature usually reaches around 26 °C (79 °F). However, it reached 30.5 °C (86.9 °F) in August 2018.
Precipitation amounts to 65 mm (2.6 in), distributed over 10 days.
The day lasts on average 16 hours and 25 minutes. So the days are long.
There are on average 7 hours of sunshine per day. So, the sun shines 42% of the time.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 13.5 °C (56.5 °F). Therefore, the sea is very cold for swimming.

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In September, the weather in Oulu is usually mild. The average temperature is of 9.5 °C (49 °F), with a minimum of 5.7 °C (42.2 °F) and a maximum of 13.3 °C (56 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -2 °C (29 °F). However, it dropped to -5.5 °C (22.1 °F) in September 1993.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 20 °C (68.5 °F). However, it reached 25.4 °C (77.7 °F) in September 2019.
Precipitation amounts to 45 mm (1.8 in), distributed over 8 days.
The day lasts on average 12 hours and 55 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 34% of the time.
The average humidity is 81%. Hence, the air is normally humid.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 11.5 °C (52.5 °F). Therefore, the sea is very cold for swimming.

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In October, the weather in Oulu is usually cold. The average temperature is of 3.1 °C (38 °F), with a minimum of 0.4 °C (32.7 °F) and a maximum of 5.8 °C (42.5 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -9.5 °C (15 °F). However, it dropped to -20.1 °C (-4.2 °F) in October 1992.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 12 °C (54 °F). However, it reached 20.5 °C (68.9 °F) in October 2018.
Precipitation amounts to 50 mm (2 in), distributed over 10 days.
The day lasts on average 9 hours and 30 minutes.
There are on average 2 hours of sunshine per day. So, the sun shines 23% of the time.
The average humidity is 87%. Hence, the air is normally humid.
The average wind speed is 12 kph (8 mph).
The average sea temperature is of 8 °C (46.5 °F). Therefore, the sea is very cold for swimming.

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In November, the weather in Oulu is usually very cold. The average temperature is of -1.9 °C (29 °F), with a minimum of -4.3 °C (24.2 °F) and a maximum of 0.5 °C (32.9 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -15.5 °C (4 °F). However, it dropped to -24.5 °C (-12.1 °F) in November 1995.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 7 °C (44.5 °F). However, it reached 11.2 °C (52.2 °F) in November 2015.
Precipitation amounts to 40 mm (1.6 in), distributed over 10 days.
The day lasts on average 6 hours and 5 minutes. So the days are short.
There is an average of 1 hour of sunshine per day. So, the sun shines 15% of the time.
The average humidity is 90%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 5 °C (41 °F). Therefore, the sea is very cold for swimming.

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In December, the weather in Oulu is usually freezing cold. The average temperature is of -5.7 °C (22 °F), with a minimum of -8.7 °C (16.3 °F) and a maximum of -2.7 °C (27.2 °F).
On the coldest nights of the month, the temperature usually drops to around -22 °C (-7.5 °F). However, it dropped to -37.2 °C (-35 °F) in December 2002.
On the warmest days of the month, the temperature usually reaches around 4.5 °C (39.5 °F). However, it reached 8.2 °C (46.8 °F) in December 2013.
Precipitation amounts to 40 mm (1.6 in), distributed over 9 days.
The day lasts on average 3 hours and 50 minutes. So the days are very short. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 0.5 hours of sunshine per day. So, the sun shines 7% of the time.
The average humidity is 90%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 2.5 °C (37 °F). Therefore, the sea is very cold for swimming.