September weather in South Lyon, MI
The average temperature in South Lyon in September is 61.8°F (50.2°F–73.5°F). Average precipitation: 3.11 inches.
September is a fall month in South Lyon, and is warmer than the annual average of 47.1°F. Daily temperatures swing about 23.3°F between overnight low and afternoon high. Daylight averages about 12h 16m. For travel, September is one of the best months of the year to visit.
Avg High
73.5°F
Avg Low
50.2°F
Precipitation
3.11 in
Daylight
12h 16m
September records in South Lyon
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 93.0°F (2012) | 43.0°F (2009) | 0.14 in (2019) |
| September 2 | 89.1°F (2011) | 43.0°F (2009) | 0.40 in (2018) |
| September 3 | 93.0°F (2011) | 44.1°F (2009) | 0.55 in (2019) |
| September 4 | 91.9°F (2011) | 46.9°F (2009) | 0.58 in (2015) |
| September 5 | 89.1°F (2018) | 42.1°F (2010) | 0.44 in (2017) |
| September 6 | 91.9°F (2014) | 42.1°F (2010) | 1.01 in (2024) |
| September 7 | 89.1°F (2015) | 39.9°F (2025) | 0.52 in (2023) |
| September 8 | 89.1°F (2015) | 39.9°F (2025) | 0.71 in (2012) |
| September 9 | 88.0°F (2015) | 39.9°F (2017) | 1.10 in (2008) |
| September 10 | 82.0°F (2022) | 39.9°F (2017) | 0.82 in (2011) |
| September 11 | 91.0°F (2013) | 41.0°F (2008) | 1.22 in (2014) |
| September 12 | 89.1°F (2013) | 43.0°F (2007) | 2.47 in (2019) |
| September 13 | 82.0°F (2024) | 42.1°F (2007) | 0.55 in (2020) |
| September 14 | 82.9°F (2012) | 37.0°F (2013) | 3.74 in (2008) |
| September 15 | 86.0°F (2021) | 36.0°F (2007) | 1.53 in (2008) |
| September 16 | 84.9°F (2018) | 36.0°F (2007) | 0.12 in (2010) |
| September 17 | 84.0°F (2018) | 36.0°F (2013) | 0.55 in (2010) |
| September 18 | 86.0°F (2018) | 36.0°F (2013) | 0.21 in (2016) |
| September 19 | 88.0°F (2025) | 33.1°F (2020) | 0.38 in (2022) |
| September 20 | 84.0°F (2016) | 36.0°F (2012) | 1.31 in (2018) |
| September 21 | 84.9°F (2007) | 41.0°F (2020) | 1.26 in (2022) |
| September 22 | 91.0°F (2017) | 39.9°F (2020) | 1.90 in (2021) |
| September 23 | 90.0°F (2017) | 37.0°F (2013) | 2.03 in (2021) |
| September 24 | 91.9°F (2017) | 37.9°F (2013) | 0.30 in (2021) |
| September 25 | 89.1°F (2017) | 35.1°F (2012) | 0.40 in (2025) |
| September 26 | 90.0°F (2017) | 37.9°F (2013) | 0.51 in (2011) |
| September 27 | 91.0°F (2017) | 39.9°F (2013) | 0.31 in (2011) |
| September 28 | 84.9°F (2025) | 42.1°F (2018) | 1.35 in (2019) |
| September 29 | 81.0°F (2025) | 39.0°F (2018) | 0.45 in (2009) |
| September 30 | 82.0°F (2025) | 39.0°F (2022) | 1.09 in (2016) |