DULUTH, MN

Overview:
Duluth, Minnesota is located on the western tip of Lake Superior and ranks as the state’s second-largest city by land area and its fourth-largest by population. Together with neighboring Superior, Wisconsin, the two cities form the Twin Ports, making up the Great Lakes’ largest port. Duluth has been called “The Air-Conditioned City” because of cooling easterly winds coming from Lake Superior in the summer.

The climate in Duluth is predominantly humid continental. Its proximity to Lake Superior, the largest and coldest of the Great Lakes, plays a large role in its climate. The lake acts as a heat sink, keeping the area relatively cooler in summer and warmer in winter. However, winters are still known for being long, snowy, and cold. Maximum temperatures remain below 32 °F an average of 106 days a year, the second most days of any city in the contiguous U.S. behind only International Falls. The average annual snowfall tops 86 inches, which is the highest reported total in the state.

State/ Province ID: MN

Station ID: W00014913

Directory Name: DULUTH__MN_W00014913

Elevation: 435.30m

The resources presented here were developed in cooperation with the Office of the Michigan State Climatologist using data from the National Climatic Data Center. For more information regarding our data sources, quality control, and methodology, please see our Historical Climatologies: Quality Control reference guide.

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Recent Climate Summary, 1991-2020

Average Temperature40.3°F4.6°C
Average Low Temperature31.3°F-0.4°C
Average High Temperature49.3°9.6°C
Days/Year that exceed 90°F1.1 
Days/Year that fall below 32°F169.7 
Lowest Annual Average Temperature36.4°F2.4°C
Highest Annual Average Temperature44.1°F6.7°C
Average Annual Total Precipitation31.2 in79.2 cm
Lowest Annual Precipitation Total21.0 in53.4 cm
Highest Annual Precipitation Total43.5 in110.4 cm
Days/Year that exceed 1.25" of Precipitation3.4 

Temperature

Click on the following links to be taken to the corresponding portion of the page.

  • Monthly Average Temperature
  • How Temperatures are Changing
    • Changes in Average Temperature – Includes a summary table of the average annual and seasonal temperature changes, and time series graphs of how the annual low, average, and high temperatures compare to the long term average plotted for every year on record.
    • Cold Temperatures – View time series plots of the number of days per year below 32°F and the number of heating degree days (?) per year to see how cold days are changing.
    • Hot Temperatures – View time series plots of the number of days per year above 90°F and the number of cooling degree days (?) per year to see how hot days are changing.
    • Growing Season Changes – View a time series of the annual number of days in the freeze-free period (?).

Monthly Average Temperature

Changes in Average Temperature, 1951-2023.

 °F°C
Annual average temperature3.52.0
Winter average temperature4.52.5
Spring average temperature3.31.8
Summer average temperature3.21.8
Fall average temperature3.01.7

Annual High and Low Temperature Departure

Cold Temperatures

¹Heating Degree Days (HDDs) are indexed units, not actual days, that roughly describe the demand to heat a building. HDDs accumulate on days colder than 65°F when heating is required. Every degree below 65°F is added to the annual total for an annual HDD value, which is plotted in the figure.

Hot Temperatures

²Cooling Degree Days (CDDs) are indexed units, not actual days, that roughly describe the demand to cool a building. CDDs accumulate on days warmer than 65°F when cooling is required. Every degree above 65°F is added to the annual total for an annual CDD value, which is plotted in the figure.

Growing Season Changes

Precipitation

Click on the following links to be taken to the corresponding portion of the page.

  • Monthly Average Precipitation – View a graph of the monthly low, average, and high precipitation climatology (average) of the past 30 years
  • How Precipitation is Changing
    • Changes in Total Precipitation – Includes a summary table of the average annual and seasonal precipitation changes.
    • Heavy Precipitation – View a time series graph of how annual number of days receiving more than 1, 1.25, 1.5, 1.75, and 2 inches of precipitation are changing over the period of record.

Monthly Average Precipitation

Changes in Average Precipitation, 1951-2023.

 in.cm.%
Annual total precipitation1.74.25.60
Winter total precipitation0.51.213.90
Spring total precipitation0.30.84.20
Summer total precipitation-1.2-3.1-10.10
Fall total precipitation1.84.424.40

Heavy Precipitation