Ann Arbor climate
Ann Arbor (Michigan, United States) has a hot-summer humid continental climate (Köppen Dfa). The average temperature over the year is 9 °C48 °F, and about 878 mm35 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Ann Arbor climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin | Frost days |
|---|---|---|---|---|---|
| Jan | −229 | −916 | −522 | 542.1 | 29 |
| Feb | 032 | −916 | −524 | 552.2 | 27 |
| Mar | 643 | −425 | 134 | 572.2 | 25 |
| Apr | 1457 | 134 | 846 | 803.1 | 13 |
| May | 2068 | 847 | 1457 | 1034.1 | 1 |
| Jun | 2578 | 1457 | 1967 | 873.4 | 0 |
| Jul | 2883 | 1762 | 2272 | 843.3 | 0 |
| Aug | 2882 | 1661 | 2271 | 833.3 | 0 |
| Sep | 2475 | 1253 | 1864 | 773.0 | 0 |
| Oct | 1660 | 541 | 1050 | 783.1 | 4 |
| Nov | 846 | −130 | 438 | 642.5 | 18 |
| Dec | 134 | −622 | −228 | 572.2 | 28 |
| Year | 2883 | −916 | 948 | 87835 | 145 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total. Frost days are for the whole grid cell.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 88% | 77% | 1.6 | 9:25 |
| Feb | 86% | 72% | 2.4 | 10:30 |
| Mar | 80% | 68% | 3.5 | 11:49 |
| Apr | 76% | 64% | 4.7 | 13:19 |
| May | 77% | 64% | 5.4 | 14:34 |
| Jun | 76% | 56% | 6.2 | 15:15 |
| Jul | 72% | 50% | 6.2 | 14:58 |
| Aug | 71% | 49% | 5.3 | 13:53 |
| Sep | 73% | 49% | 4.3 | 12:25 |
| Oct | 77% | 63% | 2.8 | 10:58 |
| Nov | 82% | 69% | 1.8 | 9:43 |
| Dec | 88% | 79% | 1.2 | 9:06 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of Ann Arbor is like
The warmest month is July, with an average high of 28 °C83 °F and a low of 17 °C62 °F. The coldest is January, when highs average −2 °C29 °F and lows −9 °C16 °F. Seasons are strongly marked: the warmest month is on average 27.7 °C49.9 °F warmer than the coldest.
Annual precipitation is moderate at about 878 mm35 in. Rain is spread fairly evenly through the year. The wettest month is May (103 mm4.1 in), the driest is January (54 mm2.1 in).
Relative humidity ranges from 71% in August to 88% in January. The clearest skies (lowest average cloud amount, 49%) are typical of September. Average wind speed near the ground ranges from 8 km/h (5 mph) in August to 15 km/h (9 mph) in February. Daylight lasts from about 9.1 hours in December to 15.3 hours in June.
A lasting snow cover is typical in December–March, when the average snow depth in the reanalysis exceeds 10 cm (deepest in January, about 17 cm).
Best time to visit Ann Arbor
Based on these averages, the most comfortable months for sightseeing and outdoor activities are June–September: average highs of 24 °C75 °F to 28 °C83 °F with 77 mm3.0 in to 87 mm3.4 in of precipitation per month.
The most challenging month is January, which is cold, with average highs of −2 °C29 °F.
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for Ann Arbor
- Winter (December–February) — highs −229 to 1 °C34 °F, lows −916 to −6 °C22 °F, about 55 mm2.2 in of precipitation a month. Pack a winter coat, hat, gloves and warm, non-slip boots and shoes with good grip, as frost is common.
- Spring (March–May) — highs 643 to 20 °C68 °F, lows −425 to 8 °C47 °F, about 80 mm3.2 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket and an extra layer for the cooler mornings and evenings.
- Summer (June–August) — highs 2578 to 28 °C83 °F, lows 1457 to 17 °C62 °F, about 85 mm3.3 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses and an extra layer for the cooler mornings and evenings.
- Autumn (September–November) — highs 846 to 24 °C75 °F, lows −130 to 12 °C53 °F, about 73 mm2.9 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket and an extra layer for the cooler mornings and evenings.
How Ann Arbor compares
Compared with Windsor, about 60 km to the east, Ann Arbor is on average 0.5 °C1 °F cooler and receives a similar amount of precipitation. The difference is largest in December (0.9 °C1.7 °F cooler).
Of the 222 places in the United States covered by World Climates, Ann Arbor is the 213th warmest by annual mean temperature and the 136th wettest by annual precipitation. See all of them on the United States climate page.
Places in other countries with the most similar temperature and rainfall pattern: Windsor (Canada, Dfa), Brantford (Canada, Dfa) and Brampton (Canada, Dfa).
Nearby places
- Windsor 60 km · 9 °C49 °F · 848 mm33 in
- Toledo 70 km · 10 °C51 °F · 906 mm36 in
- Lansing 84 km · 9 °C48 °F · 885 mm35 in
- Fort Wayne 172 km · 10 °C51 °F · 966 mm38 in
- Grand Rapids 175 km · 9 °C48 °F · 967 mm38 in
- Cleveland 190 km · 11 °C51 °F · 936 mm37 in
- South Bend 218 km · 10 °C50 °F · 994 mm39 in
- London 220 km · 9 °C48 °F · 660 mm26 in
Frequently asked questions
What is the warmest month in Ann Arbor?
July is the warmest month in Ann Arbor, with an average high of 28 °C (83 °F) and an average low of 17 °C (62 °F).
What is the coldest month in Ann Arbor?
January is the coldest month, with an average high of -2 °C (29 °F) and an average low of -9 °C (16 °F).
When does it rain the most in Ann Arbor?
May is the wettest month with about 103 mm (4.1 in) of precipitation; January is the driest with about 54 mm (2.1 in).
What is the best time to visit Ann Arbor?
Judging by long-term averages, the most comfortable months are June–September.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.