Ann Arbor weather in September: Ann Arbor, Michigan: normal highs, lows, rain and records for September
Ann Arbor in September has a normal high of 74°F and a normal low of 48°F, a daily mean of 61°F, falling from 79°F on the 1st to 69°F by the 30th. Measurable precipitation falls on 12 days in a normal September, 2.76 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 23°C and low of 9°C, 70 mm of precipitation in September.
- NOAA stationAnn Arbor Municipal Airport
- Station IDUSW00094889
- Location42.22°N 83.74°W
- Elevation839 ft (256 m)
- From the center4 miles
- Population122,925
- Jan 32° 15°
- Feb 35° 16°
- Mar 45° 25°
- Apr 59° 35°
- May 70° 46°
- Jun 79° 54°
- Jul 84° 57°
- Aug 81° 57°
- Sep 74° 48°
- Oct 62° 38°
- Nov 48° 30°
- Dec 36° 22°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Ann Arbor in September?
The normal high is 74°F and the normal low 48°F, for a daily mean of 61.3°F. September is 7.9°F cooler than August and 11.4°F warmer than October. September is the 4th warmest month of the year in Ann Arbor and the 5th wettest. Across the month the normal high falls 10°F, from 79°F on September 1 to 69°F on September 30. From one year to the next September's mean temperature typically moves about 2.7°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 59°F and 64°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 39%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 79°F | 54°F | 39% | 16% |
| September 8 | 77°F | 51°F | 39% | 16% |
| September 15 | 75°F | 49°F | 39% | 16% |
| September 22 | 72°F | 46°F | 39% | 17% |
| September 30 | 69°F | 43°F | 39% | 18% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 79°F | 54°F | 39% | 16% | 13 h 10 min |
| September 2 | 78°F | 53°F | 39% | 16% | 13 h 10 min |
| September 3 | 78°F | 53°F | 39% | 16% | 13 h 10 min |
| September 4 | 78°F | 53°F | 39% | 16% | 13 h |
| September 5 | 78°F | 52°F | 39% | 16% | 13 h |
| September 6 | 77°F | 52°F | 39% | 16% | 13 h |
| September 7 | 77°F | 52°F | 39% | 16% | 13 h |
| September 8 | 77°F | 51°F | 39% | 16% | 12 h 50 min |
| September 9 | 77°F | 51°F | 39% | 16% | 12 h 50 min |
| September 10 | 76°F | 51°F | 39% | 16% | 12 h 50 min |
| September 11 | 76°F | 50°F | 39% | 16% | 12 h 40 min |
| September 12 | 76°F | 50°F | 39% | 16% | 12 h 40 min |
| September 13 | 75°F | 49°F | 39% | 16% | 12 h 40 min |
| September 14 | 75°F | 49°F | 39% | 16% | 12 h 40 min |
| September 15 | 75°F | 49°F | 39% | 16% | 12 h 30 min |
| September 16 | 74°F | 48°F | 39% | 16% | 12 h 30 min |
| September 17 | 74°F | 48°F | 39% | 17% | 12 h 30 min |
| September 18 | 74°F | 48°F | 39% | 17% | 12 h 20 min |
| September 19 | 73°F | 47°F | 39% | 17% | 12 h 20 min |
| September 20 | 73°F | 47°F | 39% | 17% | 12 h 20 min |
| September 21 | 73°F | 46°F | 39% | 17% | 12 h 20 min |
| September 22 | 72°F | 46°F | 39% | 17% | 12 h 10 min |
| September 23 | 72°F | 46°F | 39% | 17% | 12 h 10 min |
| September 24 | 71°F | 45°F | 39% | 17% | 12 h 10 min |
| September 25 | 71°F | 45°F | 39% | 17% | 12 h 10 min |
| September 26 | 70°F | 45°F | 39% | 18% | 12 h |
| September 27 | 70°F | 44°F | 39% | 18% | 12 h |
| September 28 | 70°F | 44°F | 39% | 18% | 12 h |
| September 29 | 69°F | 44°F | 39% | 18% | 11 h 50 min |
| September 30 | 69°F | 43°F | 39% | 18% | 11 h 50 min |
- Normal high
- 74°FSeptember average
- Normal low
- 48°FSeptember average
- Precipitation
- 2.76 inmonth total
- Days with precipitation
- 120.01 inch or more
- Days at 90°F or more
- 1
- Nights at 32°F or colder
- 1
- Daylight
- 13 h 10 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 22
- Days at 80°F or more
- 9
- Sunshine
- 77%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00094889; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Ann Arbor in September?
On a given September day the chance of 0.01 inch or more is 39% on average, highest around September 8 (39%). In all, 2.76 in falls on 12 days of a normal September, 1 of them with an inch or more.
In a normal September in Ann Arbor, 1 days reach 90°F and 1 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00094889.
What are the records for September in Ann Arbor?
The warmest September temperature on this station's record (since 1998) is 95°F, on September 2, 2011; the coldest is 28°F, on September 22, 1999. The wettest September brought 5.36 in (2008).
The September mean against the 1991-2020 normal of 61.3°F: 2021 63.9°F (+2.6), 2022 62.7°F (+1.4), 2023 62.6°F (+1.4), 2024 64.1°F (+2.8), 2025 63.2°F (+1.9). 5 of 5 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 63.9°F | +2.6°F | 3.85 in |
| 2022 | 62.7°F | +1.4°F | 1.42 in |
| 2023 | 62.6°F | +1.4°F | 1.78 in |
| 2024 | 64.1°F | +2.8°F | 1.11 in |
| 2025 | 63.2°F | +1.9°F | – |
Source: records: ACIS, station USW00094889; recent months: ACIS, station USW00094889. Records and recent months use complete months only.
How does September in Ann Arbor compare across Michigan?
Across the 140 places PlainClimate covers in Michigan, September normal highs run from 65°F in Munising to 76°F in Eau Claire; Ann Arbor's is 74°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.