Climateby Month

Duluth, MN climate by month

NOAA 1991-2020 normals · 700 ft elevation

Duluth has mild summers and very cold and snowy winters. Highs peak at 76°F in July and fall to 23°F in January. The wettest month is May (about 12 wet days) and the driest is February (about 6). Normal snowfall is about 56 in a year. By our comfort score the best month is August.

Warmest month
76°F
July normal high
Coldest month
6°F
January normal low
Wet days a year
106
31.4 in of precipitation
Snow a year
56.0 in
normal snowfall

How warm is Duluth?

Normal highs range from 23°F in January to 76°F in July.

0°20°40°60°80° January: normal high 23°F (-5°C), low 6°F (-14°C) 23° 6° February: normal high 27°F (-3°C), low 9°F (-13°C) March: normal high 36°F (2°C), low 21°F (-6°C) April: normal high 46°F (8°C), low 32°F (0°C) May: normal high 57°F (14°C), low 41°F (5°C) June: normal high 67°F (19°C), low 50°F (10°C) July: normal high 76°F (24°C), low 58°F (14°C) 76° 58° August: normal high 75°F (24°C), low 58°F (14°C) September: normal high 67°F (19°C), low 50°F (10°C) October: normal high 53°F (12°C), low 39°F (4°C) November: normal high 39°F (4°C), low 26°F (-3°C) December: normal high 27°F (-3°C), low 13°F (-11°C) JFMAMJJASOND

Bars run from the normal low to the normal high for each month.

How rainy is Duluth?

May has the most wet days (about 12); the year brings about 31 in of precipitation.

January: 7 wet days February: 6 wet days 6 March: 7 wet days April: 9 wet days May: 12 wet days 12 June: 12 wet days July: 10 wet days August: 10 wet days September: 10 wet days October: 10 wet days November: 8 wet days December: 7 wet days JFMAMJJASOND

Wet day: at least 0.01 in of rain or melted snow, counted from daily records 1991-2020.

How much does it snow?

Normal snowfall is 56.0 in a year, most of it in January.

January: 14.5 in of snow 14.5 February: 12.4 in of snow March: 9.1 in of snow April: 1.7 in of snow May: 0.0 in of snow 0.0 June: 0.0 in of snow July: 0.0 in of snow August: 0.0 in of snow September: 0.0 in of snow October: 0.2 in of snow November: 5.8 in of snow December: 12.3 in of snow JFMAMJJASOND

How humid is Duluth?

Muggy days peak in July, at about 2 days.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 0 muggy days June: 0 muggy days July: 2 muggy days 2 August: 2 muggy days September: 0 muggy days October: 0 muggy days November: 0 muggy days December: 0 muggy days JFMAMJJASOND

Muggy day: daily mean dew point of 65°F or higher, from hourly observations 1991-2020 at Duluth International Airport, 5.7 mi NW of the city center.

How much daylight?

Daylight ranges from about 8.6 hours in December to 15.8 hours in June.

January: 9.0 hours of daylight February: 10.3 hours of daylight March: 11.9 hours of daylight April: 13.6 hours of daylight May: 15.1 hours of daylight June: 15.8 hours of daylight 15.8 July: 15.4 hours of daylight August: 14.2 hours of daylight September: 12.6 hours of daylight October: 10.9 hours of daylight November: 9.4 hours of daylight December: 8.6 hours of daylight 8.6 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for Duluth, 1991-2020
MonthHighLowPrecip.Wet daysSnowMuggy daysDaylight
January 23°F6°F 0.8 in7 14.5 in 0 9.0 h
February 27°F9°F 0.9 in6 12.4 in 0 10.3 h
March 36°F21°F 1.4 in7 9.1 in 0 11.9 h
April 46°F32°F 2.6 in9 1.7 in 0 13.6 h
May 57°F41°F 3.4 in12 0.0 in 0 15.1 h
June 67°F50°F 4.6 in12 0.0 in 0 15.8 h
July 76°F58°F 3.9 in10 0.0 in 2 15.4 h
August 75°F58°F 3.9 in10 0.0 in 2 14.2 h
September 67°F50°F 3.4 in10 0.0 in 0 12.6 h
October 53°F39°F 3.2 in10 0.2 in 0 10.9 h
November 39°F26°F 2.1 in8 5.8 in 0 9.4 h
December 27°F13°F 1.3 in7 12.3 in 0 8.6 h

High and low: NOAA 1991-2020 normal daily high and low. Wet days: at least 0.01 in of rain or melted snow. Muggy days: daily mean dew point 65°F or higher.

Best months to visit Duluth

By our comfort score, the best month is August.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 230330
Feb 280326
Mar 350422
Apr 472611
May 63781
Jun 681281
Jul 681172
Aug 731671
Sep 661360
Oct 48462
Nov 321417
Dec 240329

Score = 40 × share of comfortable days + 25 × share of days without notable rain + 20 × share of days neither hot (90°F+) nor cold (high 40°F or below) + 15 × daylight. How the score works.

Frost dates in Duluth

The last spring frost typically comes around May 6, and the first fall frost around Oct 9, leaving 154 frost-free days in a typical year.

Frost and freeze dates for Duluth
Typical date1 year in 10
Last spring frost (32°F)May 6after May 25
First fall frost (32°F)Oct 9before Sep 24
Last hard freeze (28°F)Apr 24after May 9
First hard freeze (28°F)Oct 24before Oct 6
Frost-free season154 daysunder 132 days

"Typical" is the date with a 50% chance of a later spring frost (or earlier fall frost). Planting after the "1 year in 10" spring date gives a 90% chance of no further frost. The Old Farmer's Almanac publishes 30% dates, which fall between our typical and 1-in-10 dates.

Station: Superior (USC00478349), NOAA 1991-2020 freeze probabilities. Frost dates for every city in Minnesota.

Hottest and coldest readings, 1991-2020

The highest reading was 101°F (July 28, 2006, and 1 other day); the lowest was -37°F (February 2, 1996).

From the temperature station's daily records with NOAA quality flags removed. Not an all-time record.

Near Duluth

Similar climates elsewhere

Where the numbers come from

  • Temperature, rain, snowfall, snow depth and frost dates: Superior (USC00478349), 4.2 mi SSE of the city center, 607 ft (93 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Humidity and wind by hour and cloud cover: Duluth (USW00014913), 6.1 mi NW of the city center, 1,428 ft (728 ft higher than the city). NOAA normals and daily records, 1991-2020.
  • Daily humidity and wind: Duluth International Airport (727450-14913), 5.7 mi NW of the city center, 1,422 ft (722 ft higher than the city). Hourly observations, 1991-2020.

Distances from the city center (USGS). Methodology · Report an error