Duluth is a city of 85,000 inhabitants, located in the northern United States, in Minnesota, on the western coast of Lake Superior (the northernmost of the Great Lakes), at 200 meters (650 feet) above sea level and almost 47 degrees north latitude.
is moderate, amounting to 790 millimeters (31 inches) per year. Summer is the rainiest season, also due to afternoon thunderstorms.
Winter is the driest season, however, under certain weather conditions, with the northeast wind that brings humid air from the lake (
fall per year. Snow covers the ground from late November to early April. It usually snows from October to April, but it can occasionally snow even in May.
The year 2022-2023 was the snowiest, with a total of 355 cm (140 in). On November 1, 1991, 61 cm (24 in) of snow fell in one day.
, from mid-November to mid-March, is very cold, with temperatures commonly below freezing even during the day. In fact, Duluth is one of the coldest cities in the United States.
are severe. The temperature drops below -25 °C (-13 °F) every year, and once every few years even below -35 °C (-31 °F). In recent decades, the coldest record is -39.5 °C (-39.1 °F), set in February 1996. In January 1994, the monthly daily average was -18.2 °C (-0.8 °F).
partially freezes in the winter, reaching its maximum in early March. In the coldest winters it can freeze completely; the last time this happened was in 1996.
, from June to August, is quite warm and sunny, although thunderstorms can break out in the afternoon, in addition, there may be some rainy days.
The breeze from the lake cools the air, making very hot days rare. In fact, the temperature reaches or exceeds 32 °C (89.5 °F) only two days a year on average. However, it can occasionally reach 35/36 °C (95/97 °F). In 2023, it reached 36 °C (97 °F) for a couple of days in early September.
In summer, the lake is usually cold enough to swim in, however, it depends on the year and the period: sometimes it can become quite tepid, at least in July and August.
, from mid-March to May and from September to mid-November, are unsettled seasons, with quite frequent rains and temperature changes.
to visit Duluth is in the summer and early fall, from June to mid-September, to avoid the cold that can occur in the other seasons, and because it rarely gets very hot.
The following data refers to the international airport, which is a little colder than the city because it is located at 435 meters (1,425 ft) above sea level and a few kilometers away from the lake.
. Here are the average temperatures.
January, the coldest month of the year, is generally a freezing cold month. The average temperature is of
-11.5 °C, with a minimum of
-16.4 °C and a maximum of
-6.7 °C.
On the coldest nights of the month, the temperature usually drops to around
-30 °C. However, it dropped to
-37.2 °C in January 1994.
On the warmest days of the month, the temperature usually reaches around
3.5 °C. However, it reached
8.9 °C in January 2003.
Precipitation amounts to
24 mm, distributed over 6 days.
The day lasts on average 9 hours and 5 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 47% of the time.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is of
16.9 kph.
February is generally a freezing cold month. The average temperature is of
-9.2 °C, with a minimum of
-14.5 °C and a maximum of
-4 °C.
On the coldest nights of the month, the temperature usually drops to around
-27 °C. However, it dropped to
-39.5 °C in February 1996.
On the warmest days of the month, the temperature usually reaches around
6.5 °C. However, it reached
12.8 °C in February 2000.
Precipitation amounts to
25.6 mm, distributed over 5 days.
The day lasts on average 10 hours and 25 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 51% of the time.
The average humidity is 70%. Hence, the air is normally humid.
The average wind speed is of
16.8 kph.
March is generally a very cold month. The average temperature is of
-2.8 °C, with a minimum of
-7.9 °C and a maximum of
2.3 °C.
On the coldest nights of the month, the temperature usually drops to around
-22 °C. However, it dropped to
-30.6 °C in March 2014.
On the warmest days of the month, the temperature usually reaches around
13 °C. However, it reached
23.9 °C in March 2012.
Precipitation amounts to
37.1 mm, distributed over 6 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 51% of the time.
The average humidity is 68%.
The average wind speed is of
16.5 kph.
April is generally a quite cold month. The average temperature is of
4.2 °C, with a minimum of
-1.2 °C and a maximum of
9.5 °C.
On the coldest nights of the month, the temperature usually drops to around
-9.5 °C. However, it dropped to
-18.3 °C in April 1995.
On the warmest days of the month, the temperature usually reaches around
21.5 °C. However, it reached
27 °C in April 2003.
Precipitation amounts to
64.2 mm, distributed over 8 days.
The day lasts on average 13 hours and 40 minutes.
There are on average 7.5 hours of sunshine per day. So, the sun shines 56% of the time.
The average humidity is 61%.
The average wind speed is of
17.7 kph.
May is generally a mild month. The average temperature is of
11.1 °C, with a minimum of
5 °C and a maximum of
17.2 °C.
On the coldest nights of the month, the temperature usually drops to around
-1.5 °C. However, it dropped to
-6.7 °C in May 2002.
On the warmest days of the month, the temperature usually reaches around
27.5 °C. However, it reached
33.3 °C in May 2018.
Precipitation amounts to
85.7 mm, distributed over 10 days.
The day lasts on average 15 hours and 5 minutes. So the days are long.
There are on average 8.5 hours of sunshine per day. So, the sun shines 56% of the time.
The average humidity is 61%.
The average wind speed is of
16.8 kph.
June is generally a very mild month. The average temperature is of
16.2 °C, with a minimum of
10.1 °C and a maximum of
22.3 °C.
On the coldest nights of the month, the temperature usually drops to around
3.5 °C. However, it dropped to
-1.1 °C in June 1992.
On the warmest days of the month, the temperature usually reaches around
30 °C. However, it reached
34.4 °C in June 1995.
Precipitation amounts to
111.5 mm, distributed over 10 days.
The day lasts on average 15 hours and 50 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 9 hours of sunshine per day. So, the sun shines 57% of the time.
The average humidity is 69%.
The average wind speed is of
14.9 kph.
July, the warmest month of the year, is generally a warm month. The average temperature is of
19.4 °C, with a minimum of
13.5 °C and a maximum of
25.4 °C.
On the coldest nights of the month, the temperature usually drops to around
7.5 °C. However, it dropped to
4.4 °C in July 1991.
On the warmest days of the month, the temperature usually reaches around
31.5 °C. However, it reached
36 °C in July 2006.
Precipitation amounts to
99.7 mm, distributed over 9 days.
The day lasts on average 15 hours and 25 minutes. So the days are long.
There are on average 10 hours of sunshine per day. So, the sun shines 64% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is of
13.7 kph.
August is generally a warm month. The average temperature is of
18.6 °C, with a minimum of
12.9 °C and a maximum of
24.3 °C.
On the coldest nights of the month, the temperature usually drops to around
7 °C. However, it dropped to
2.2 °C in August 2004.
On the warmest days of the month, the temperature usually reaches around
30.5 °C. However, it reached
35 °C in August 2006.
Precipitation amounts to
94.8 mm, distributed over 8 days.
The day lasts on average 14 hours and 5 minutes. So the days are long.
There are on average 8.5 hours of sunshine per day. So, the sun shines 60% of the time.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is of
13.5 kph.
September is generally a mild month. The average temperature is of
14 °C, with a minimum of
8.5 °C and a maximum of
19.5 °C.
On the coldest nights of the month, the temperature usually drops to around
0.5 °C. However, it dropped to
-3.3 °C in September 2000.
On the warmest days of the month, the temperature usually reaches around
28 °C. However, it reached
31.1 °C in September 2002.
Precipitation amounts to
88.3 mm, distributed over 9 days.
The day lasts on average 12 hours and 30 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 52% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is of
15.2 kph.
October is generally a quite mild month. The average temperature is of
6.8 °C, with a minimum of
2 °C and a maximum of
11.5 °C.
On the coldest nights of the month, the temperature usually drops to around
-5.5 °C. However, it dropped to
-12 °C in October 1996.
On the warmest days of the month, the temperature usually reaches around
23.5 °C. However, it reached
28.9 °C in October 1992.
Precipitation amounts to
74 mm, distributed over 9 days.
The day lasts on average 10 hours and 50 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 45% of the time.
The average humidity is 72%. Hence, the air is normally humid.
The average wind speed is of
16.8 kph.
November is generally a very cold month. The average temperature is of
-1.2 °C, with a minimum of
-5.3 °C and a maximum of
2.8 °C.
On the coldest nights of the month, the temperature usually drops to around
-16 °C. However, it dropped to
-22.8 °C in November 2014.
On the warmest days of the month, the temperature usually reaches around
13 °C. However, it reached
23.9 °C in November 2020.
Precipitation amounts to
49.8 mm, distributed over 7 days.
The day lasts on average 9 hours and 20 minutes.
There are on average 3.5 hours of sunshine per day. So, the sun shines 35% of the time.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is of
16.8 kph.
December is generally a freezing cold month. The average temperature is of
-8.3 °C, with a minimum of
-12.5 °C and a maximum of
-4.1 °C.
On the coldest nights of the month, the temperature usually drops to around
-25.5 °C. However, it dropped to
-31.7 °C in December 1993.
On the warmest days of the month, the temperature usually reaches around
4.5 °C. However, it reached
12 °C in December 1998.
Precipitation amounts to
37.4 mm, distributed over 6 days.
The day lasts on average 8 hours and 35 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 3.5 hours of sunshine per day. So, the sun shines 38% of the time.
The average humidity is 78%. Hence, the air is normally humid.
The average wind speed is of
16.4 kph.