Climateby Month

Ann Arbor, MI climate by month

NOAA 1991-2020 normals · 881 ft elevation

Ann Arbor has warm and often humid summers and cold and snowy winters. Highs peak at 84°F in July and fall to 32°F in January. Wet days are spread through the year, from about 11 to 18 a month. Normal snowfall is about 61 in a year. By our comfort score the best month is May.

Warmest month
84°F
July normal high
Coldest month
16°F
January normal low
Wet days a year
166
38.3 in of precipitation
Snow a year
61.4 in
normal snowfall

How warm is Ann Arbor?

Normal highs range from 32°F in January to 84°F in July.

0°20°40°60°80°100° January: normal high 32°F (0°C), low 16°F (-9°C) 32° 16° February: normal high 35°F (2°C), low 18°F (-8°C) March: normal high 46°F (8°C), low 25°F (-4°C) April: normal high 60°F (16°C), low 36°F (2°C) May: normal high 71°F (22°C), low 47°F (8°C) June: normal high 80°F (27°C), low 56°F (13°C) July: normal high 84°F (29°C), low 60°F (16°C) 84° 60° August: normal high 82°F (28°C), low 59°F (15°C) September: normal high 75°F (24°C), low 52°F (11°C) October: normal high 62°F (17°C), low 41°F (5°C) November: normal high 48°F (9°C), low 31°F (-1°C) December: normal high 36°F (2°C), low 22°F (-6°C) JFMAMJJASOND

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

How rainy is Ann Arbor?

January has the most wet days (about 18); the year brings about 38 in of precipitation.

January: 18 wet days 18 February: 14 wet days March: 14 wet days April: 14 wet days May: 15 wet days June: 12 wet days July: 12 wet days August: 11 wet days September: 11 wet days 11 October: 13 wet days November: 14 wet days December: 17 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 61.4 in a year, most of it in January.

January: 18.3 in of snow 18.3 February: 15.3 in of snow March: 8.3 in of snow April: 2.6 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: 0.1 in of snow November: 4.1 in of snow December: 12.7 in of snow JFMAMJJASOND

How humid is Ann Arbor?

Muggy days peak in July, at about 10 days.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 1 muggy days June: 5 muggy days July: 10 muggy days 10 August: 9 muggy days September: 3 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 Willow Run Airport, 11 mi ESE of the city center.

How much daylight?

Daylight ranges from about 9.2 hours in December to 15.2 hours in June.

January: 9.5 hours of daylight February: 10.6 hours of daylight March: 11.9 hours of daylight April: 13.4 hours of daylight May: 14.6 hours of daylight June: 15.2 hours of daylight 15.2 July: 14.9 hours of daylight August: 13.8 hours of daylight September: 12.5 hours of daylight October: 11.1 hours of daylight November: 9.8 hours of daylight December: 9.2 hours of daylight 9.2 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for Ann Arbor, 1991-2020
MonthHighLowPrecip.Wet daysSnowMuggy daysDaylight
January 32°F16°F 3.0 in18 18.3 in 0 9.5 h
February 35°F18°F 2.5 in14 15.3 in 0 10.6 h
March 46°F25°F 2.8 in14 8.3 in 0 11.9 h
April 60°F36°F 3.4 in14 2.6 in 0 13.4 h
May 71°F47°F 3.8 in15 0.0 in 1 14.6 h
June 80°F56°F 3.9 in12 0.0 in 5 15.2 h
July 84°F60°F 3.5 in12 0.0 in 10 14.9 h
August 82°F59°F 3.5 in11 0.0 in 9 13.8 h
September 75°F52°F 3.2 in11 0.0 in 3 12.5 h
October 62°F41°F 3.0 in13 0.1 in 0 11.1 h
November 48°F31°F 2.8 in14 4.1 in 0 9.8 h
December 36°F22°F 2.8 in17 12.7 in 0 9.2 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 Ann Arbor

By our comfort score, the best month is May.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 240825
Feb 290620
Mar 443611
Apr 61981
May 741780
Jun 681273
Jul 58676
Aug 62962
Sep 691661
Oct 591170
Nov 39278
Dec 260722

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 Ann Arbor

The last spring frost typically comes around May 3, and the first fall frost around Oct 13, leaving 160 frost-free days in a typical year.

Frost and freeze dates for Ann Arbor
Typical date1 year in 10
Last spring frost (32°F)May 3after May 20
First fall frost (32°F)Oct 13before Sep 29
Last hard freeze (28°F)Apr 23after May 9
First hard freeze (28°F)Oct 26before Oct 12
Frost-free season160 daysunder 138 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: Ann Arbor U Of Mich (USC00200230), NOAA 1991-2020 freeze probabilities. Frost dates for every city in Michigan.

Hottest and coldest readings, 1991-2020

The highest reading was 100°F (June 28, 2012); the lowest was -22°F (January 19, 1994).

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

Near Ann Arbor

Similar climates elsewhere

Where the numbers come from

  • Temperature, rain, snowfall, snow depth and frost dates: Ann Arbor U Of Mich (USC00200230), 3.7 mi ENE of the city center, 813 ft (68 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Humidity and wind by hour: Detroit Willow Run Airport (USW00014853), 10 mi ESE of the city center, 777 ft (104 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Cloud cover: Toledo Express Airport (USW00094830), 47 mi S of the city center, 669 ft (212 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Daily humidity and wind: Willow Run Airport (725376-14853), 11 mi ESE of the city center, 708 ft (173 ft lower than the city). Hourly observations, 1991-2020.

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