Climate - Sundsvall (Sweden)

The climate of Sundsvall is cold continental, with very cold winters, during which the temperature is often below freezing, and mild summers.
The city is located in central Sweden, on the Gulf of Bothnia coast.
Given the latitude (62°24'N), the white nights, in which the sun sets but it does not get completely dark even at midnight, occur from May 3 to August 9.
In winter, during polar cold spells, the temperature can drop to -25 °C (-13 °F) or below. The coldest record is -36.6 °C (-33.9 °F) and was set in December 1978.
In summer, the temperature can reach 28/30 °C (82/86 °F). The highest record is 33 °C (91.4 °F) and was set in July 1994.

Best Time

The best time to visit Sundsvall 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.

Sundsvall - Climate data

In Sundsvall, the average temperature of the coldest month (January) is of -6.3 °C (20.7 °F), that of the warmest month (July) is of 16.1 °C (60.9 °F). Here are the average temperatures.
In Sundsvall, precipitation amounts to 585 millimeters (23 inches) per year: so, it is at an intermediate level. It ranges from 30 mm (1.2 in) in the driest months (February, March) to 75 mm (3 in) in the wettest one (August). Here is the average precipitation.
At Sundsvall, the sea temperature ranges from 0.5 °C (33 °F) in February to 16 °C (61 °F) in August. Here are the average sea temperatures.
In Sundsvall, there are on average around 1805 sunshine hours per year. Here are the average hours of sunshine per day.

Sundsvall - Weather by month

Based on the period 1991-2020

---

In January, the coldest month of the year, the weather in Sundsvall is usually freezing cold. The average temperature is of -6.3 °C (21 °F), with a minimum of -10.6 °C (12.9 °F) and a maximum of -1.9 °C (28.5 °F).
On the coldest nights of the month, the temperature usually drops to around -22 °C (-8 °F). However, it dropped to -33.1 °C (-27.6 °F) in January 2003.
On the warmest days of the month, the temperature usually reaches around 6 °C (42.5 °F). However, it reached 11 °C (51.8 °F) in January 1992.
Precipitation amounts to 45 mm (1.8 in), distributed over 9 days.
The day lasts on average 6 hours and 10 minutes. So the days are short.
There are on average 1.5 hours of sunshine per day. So, the sun shines 22% of the time.
The average humidity is 88%. Hence, the air is normally humid.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 1.5 °C (34.5 °F). Therefore, the sea is very cold for swimming.

---

In February, the weather in Sundsvall is usually freezing cold. The average temperature is of -6.0 °C (21 °F), with a minimum of -10.9 °C (12.3 °F) and a maximum of -1.1 °C (30 °F).
On the coldest nights of the month, the temperature usually drops to around -21.5 °C (-6.5 °F). However, it dropped to -32.1 °C (-25.8 °F) in February 2010.
On the warmest days of the month, the temperature usually reaches around 7 °C (44.5 °F). However, it reached 10.7 °C (51.3 °F) in February 2015.
Precipitation amounts to 30 mm (1.2 in), distributed over 7 days.
The day lasts on average 8 hours and 55 minutes.
There are on average 3 hours of sunshine per day. So, the sun shines 32% of the time.
The average humidity is 85%. Hence, the air is normally humid.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 0.5 °C (33.5 °F). Therefore, the sea is very cold for swimming.

---

In March, the weather in Sundsvall is usually very cold. The average temperature is of -1.8 °C (29 °F), with a minimum of -6.7 °C (19.9 °F) and a maximum of 3.2 °C (37.7 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -17 °C (1 °F). However, it dropped to -26.2 °C (-15.2 °F) in March 2018.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 11 °C (52 °F). However, it reached 15.2 °C (59.4 °F) in March 2002.
Precipitation amounts to 30 mm (1.2 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 77%. Hence, the air is normally humid.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 1 °C (34 °F). Therefore, the sea is very cold for swimming.

---

In April, the weather in Sundsvall is usually cold. The average temperature is of 2.9 °C (37 °F), with a minimum of -2.2 °C (28 °F) and a maximum of 8 °C (46.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -8 °C (17.5 °F). However, it dropped to -15.6 °C (3.9 °F) in April 2006.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 16.5 °C (62 °F). However, it reached 22 °C (71.6 °F) in April 1993.
Precipitation amounts to 35 mm (1.4 in), distributed over 6 days.
The day lasts on average 15 hours and 0 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 41% 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 2 °C (35.5 °F). Therefore, the sea is very cold for swimming.

---

In May, the weather in Sundsvall is usually quite mild. The average temperature is of 8.0 °C (46 °F), with a minimum of 2.4 °C (36.2 °F) and a maximum of 13.6 °C (56.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -3 °C (27 °F). However, it dropped to -5 °C (23 °F) in May 2013.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 22 °C (71.5 °F). However, it reached 28 °C (82.4 °F) in May 2018.
Precipitation amounts to 40 mm (1.6 in), distributed over 8 days.
The day lasts on average 17 hours and 55 minutes. So the days are very long.
There are on average 8.5 hours of sunshine per day. So, the sun shines 47% of the time.
The average humidity is 67%.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 4.5 °C (40 °F). Therefore, the sea is very cold for swimming.

---

In June, the weather in Sundsvall is usually mild. The average temperature is of 12.9 °C (55 °F), with a minimum of 7.4 °C (45.4 °F) and a maximum of 18.4 °C (65 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 2 °C (36 °F). However, it dropped to -1.1 °C (30 °F) in June 2017.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 25.5 °C (77.5 °F). However, it reached 31 °C (87.8 °F) in June 2006.
Precipitation amounts to 50 mm (2 in), distributed over 9 days.
The day lasts on average 19 hours and 50 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 9.5 hours of sunshine per day. So, the sun shines 48% of the time.
The average humidity is 67%.
The average wind speed is 12 kph (8 mph).
The average sea temperature is of 9.5 °C (48.5 °F). Therefore, the sea is very cold for swimming.

---

In July, the warmest month of the year, the weather in Sundsvall is usually very mild. The average temperature is of 16.1 °C (61 °F), with a minimum of 11 °C (51.7 °F) and a maximum of 21.2 °C (70.1 °F).
On the coldest nights of the month, the temperature usually drops to around 6 °C (43 °F). However, it dropped to 2.9 °C (37.2 °F) in July 2019.
On the warmest days of the month, the temperature usually reaches around 27.5 °C (81 °F). However, it reached 33 °C (91.4 °F) in July 1994.
Precipitation amounts to 65 mm (2.6 in), distributed over 8 days.
The day lasts on average 18 hours and 40 minutes. So the days are very long.
There are on average 8.5 hours of sunshine per day. So, the sun shines 46% of the time.
The average humidity is 72%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 14.5 °C (58.5 °F). Therefore, the sea is very cold for swimming.

---

In August, the weather in Sundsvall is usually very mild. The average temperature is of 14.8 °C (59 °F), with a minimum of 9.8 °C (49.6 °F) and a maximum of 19.9 °C (67.7 °F).
On the coldest nights of the month, the temperature usually drops to around 4.5 °C (40.5 °F). However, it dropped to 1.4 °C (34.5 °F) in August 2007.
On the warmest days of the month, the temperature usually reaches around 26 °C (78.5 °F). However, it reached 30 °C (86 °F) in August 2006.
Precipitation amounts to 75 mm (3 in), distributed over 10 days.
The day lasts on average 15 hours and 55 minutes. So the days are long.
There are on average 7 hours of sunshine per day. So, the sun shines 44% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 16 °C (61 °F). Therefore, the sea is cold for swimming.

---

In September, the weather in Sundsvall is usually mild. The average temperature is of 10.2 °C (50 °F), with a minimum of 5.4 °C (41.6 °F) and a maximum of 15 °C (59.1 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -0.5 °C (31.5 °F). However, it dropped to -3.7 °C (25.3 °F) in September 2014.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 21 °C (70 °F). However, it reached 27.2 °C (81 °F) in September 1999.
Precipitation amounts to 55 mm (2.2 in), distributed over 8 days.
The day lasts on average 12 hours and 50 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 37% of the time.
The average humidity is 81%. Hence, the air is normally humid.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 13 °C (55 °F). Therefore, the sea is very cold for swimming.

---

In October, the weather in Sundsvall is usually quite cold. The average temperature is of 4.2 °C (40 °F), with a minimum of 0.2 °C (32.4 °F) and a maximum of 8.2 °C (46.8 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -7 °C (20 °F). However, it dropped to -15.2 °C (4.6 °F) in October 1992.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 14.5 °C (58 °F). However, it reached 21.5 °C (70.7 °F) in October 2018.
Precipitation amounts to 60 mm (2.4 in), distributed over 9 days.
The day lasts on average 9 hours and 50 minutes.
There are on average 3 hours of sunshine per day. So, the sun shines 32% of the time.
The average humidity is 85%. Hence, the air is normally humid.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 8.5 °C (47.5 °F). Therefore, the sea is very cold for swimming.

---

In November, the weather in Sundsvall is usually very cold. The average temperature is of -0.9 °C (30 °F), with a minimum of -4.1 °C (24.7 °F) and a maximum of 2.3 °C (36.1 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -12 °C (10.5 °F). However, it dropped to -22.1 °C (-7.8 °F) in November 2010.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 8.5 °C (47.5 °F). However, it reached 14 °C (57.2 °F) in November 1999.
Precipitation amounts to 55 mm (2.2 in), distributed over 10 days.
The day lasts on average 6 hours and 55 minutes. So the days are short.
There are on average 2 hours of sunshine per day. So, the sun shines 27% of the time.
The average humidity is 89%. Hence, the air is normally humid.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 5 °C (41.5 °F). Therefore, the sea is very cold for swimming.

---

In December, the weather in Sundsvall is usually very cold. The average temperature is of -4.4 °C (24 °F), with a minimum of -8.2 °C (17.2 °F) and a maximum of -0.6 °C (30.9 °F).
On the coldest nights of the month, the temperature usually drops to around -17.5 °C (0.5 °F). However, it dropped to -30.8 °C (-23.4 °F) in December 2010.
On the warmest days of the month, the temperature usually reaches around 6.5 °C (44 °F). However, it reached 10.5 °C (50.9 °F) in December 2006.
Precipitation amounts to 50 mm (2 in), distributed over 10 days.
The day lasts on average 5 hours and 10 minutes. So the days are short. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There is an average of 1 hour of sunshine per day. So, the sun shines 21% of the time.
The average humidity is 90%. Hence, the air is normally humid.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 3 °C (37.5 °F). Therefore, the sea is very cold for swimming.