| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 0.1° | -8.3° | 74.5mm | 18.4 | 0 |
| February | 1.6° | -8.7° | 65.2mm | 14.1 | 2 |
| March | 8° | -3.8° | 75.5mm | 14 | 25 |
| April | 14.9° | 1.5° | 80.9mm | 13.7 | 56 |
| May | 21.7° | 7.9° | 100mm | 14.6 | 71 |
| June | 26.7° | 13.1° | 106.2mm | 12 | 76 |
| July | 28.7° | 15.4° | 101.5mm | 11.4 | 70 |
| August | 27.8° | 14.6° | 92.8mm | 10.7 | 75 |
| September | 24.4° | 10.6° | 74.2mm | 10.3 | 79 |
| October | 17.1° | 4.4° | 70.1mm | 13.5 | 64 |
| November | 9.5° | -1.1° | 66.7mm | 12.4 | 37 |
| December | 3° | -4.6° | 71.4mm | 16.9 | 6 |
January in Ann Arbor averages a daily high of 0.1°C with nights around -8.3°C. Expect roughly 18.4 wet days totalling 74.5mm. A hard month to visit for comfort alone.
February in Ann Arbor averages a daily high of 1.6°C with nights around -8.7°C. Expect roughly 14.1 wet days totalling 65.2mm. A hard month to visit for comfort alone.
March in Ann Arbor averages a daily high of 8°C with nights around -3.8°C. Expect roughly 14 wet days totalling 75.5mm. A hard month to visit for comfort alone.
April in Ann Arbor averages a daily high of 14.9°C with nights around 1.5°C. Expect roughly 13.7 wet days totalling 80.9mm. Generally workable, with some weather to plan around.
May in Ann Arbor averages a daily high of 21.7°C with nights around 7.9°C. Expect roughly 14.6 wet days totalling 100mm. Generally workable, with some weather to plan around.
June in Ann Arbor averages a daily high of 26.7°C with nights around 13.1°C. Expect roughly 12 wet days totalling 106.2mm. Comfortable conditions for being outdoors all day.
July in Ann Arbor averages a daily high of 28.7°C with nights around 15.4°C. Expect roughly 11.4 wet days totalling 101.5mm. Generally workable, with some weather to plan around.
August in Ann Arbor averages a daily high of 27.8°C with nights around 14.6°C. Expect roughly 10.7 wet days totalling 92.8mm. Comfortable conditions for being outdoors all day.
September in Ann Arbor averages a daily high of 24.4°C with nights around 10.6°C. Expect roughly 10.3 wet days totalling 74.2mm. Comfortable conditions for being outdoors all day.
October in Ann Arbor averages a daily high of 17.1°C with nights around 4.4°C. Expect roughly 13.5 wet days totalling 70.1mm. Generally workable, with some weather to plan around.
November in Ann Arbor averages a daily high of 9.5°C with nights around -1.1°C. Expect roughly 12.4 wet days totalling 66.7mm. Demanding conditions — pack for it and plan indoor options.
December in Ann Arbor averages a daily high of 3°C with nights around -4.6°C. Expect roughly 16.9 wet days totalling 71.4mm. A hard month to visit for comfort alone.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Ann Arbor peaks at 79.
Based on 30 years of records, May–June scores highest for comfort in Ann Arbor, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 28.7°C.
June is the wettest, averaging 106.2mm of rain across roughly 12 wet days.
January is the coolest month, with average daily highs around 0.1°C.