September weather in Sister Bay, WI
The average temperature in Sister Bay in September is 60.8°F (51.2°F–70.3°F). Average precipitation: 3.41 inches.
September is a fall month in Sister Bay, and is warmer than the annual average of 44.7°F. Daily temperatures swing about 19.1°F between overnight low and afternoon high. Expect about 9 days with precipitation. Daylight averages about 12h 18m. For travel, September is one of the best months of the year to visit.
Avg High
70.3°F
Avg Low
51.2°F
Precipitation
3.41 in
Daylight
12h 18m
September records in Sister Bay
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 84.9°F (2010) | 41.0°F (2009) | 1.05 in (2010) |
| September 2 | 87.1°F (2008) | 43.0°F (2017) | 0.19 in (2020) |
| September 3 | 87.1°F (2008) | 46.9°F (2021) | 2.23 in (2015) |
| September 4 | 90.0°F (2023) | 46.9°F (2025) | 0.85 in (2014) |
| September 5 | 87.1°F (2023) | 39.0°F (2022) | 6.25 in (2014) |
| September 6 | 80.1°F (2016) | 37.9°F (2011) | 0.64 in (2023) |
| September 7 | 86.0°F (2015) | 39.0°F (2011) | 0.94 in (2021) |
| September 8 | 82.9°F (2013) | 43.0°F (2025) | 0.20 in (2017) |
| September 9 | 81.0°F (2011) | 41.0°F (2017) | 0.87 in (2015) |
| September 10 | 82.0°F (2013) | 42.1°F (2010) | 0.58 in (2019) |
| September 11 | 86.0°F (2013) | 37.9°F (2020) | 0.70 in (2014) |
| September 12 | 84.0°F (2011) | 39.0°F (2020) | 1.73 in (2022) |
| September 13 | 84.9°F (2011) | 37.9°F (2015) | 0.93 in (2019) |
| September 14 | 82.0°F (2009) | 37.9°F (2013) | 0.16 in (2008) |
| September 15 | 84.0°F (2009) | 39.0°F (2010) | 0.43 in (2019) |
| September 16 | 84.0°F (2018) | 35.1°F (2011) | 0.99 in (2010) |
| September 17 | 82.9°F (2025) | 36.0°F (2013) | 0.25 in (2016) |
| September 18 | 87.1°F (2018) | 33.1°F (2020) | 0.80 in (2015) |
| September 19 | 79.0°F (2021) | 32.0°F (2020) | 1.72 in (2019) |
| September 20 | 79.0°F (2008) | 39.9°F (2010) | 0.54 in (2014) |
| September 21 | 80.1°F (2024) | 41.0°F (2012) | 0.57 in (2014) |
| September 22 | 80.1°F (2017) | 37.9°F (2014) | 0.37 in (2016) |
| September 23 | 89.1°F (2017) | 35.1°F (2022) | 1.18 in (2010) |
| September 24 | 89.1°F (2017) | 34.0°F (2012) | 1.32 in (2010) |
| September 25 | 89.1°F (2017) | 39.9°F (2013) | 0.31 in (2011) |
| September 26 | 86.0°F (2017) | 39.9°F (2022) | 0.85 in (2016) |
| September 27 | 78.1°F (2024) | 34.0°F (2012) | 0.67 in (2011) |
| September 28 | 78.1°F (2014) | 35.1°F (2012) | 0.59 in (2009) |
| September 29 | 79.0°F (2014) | 33.1°F (2022) | 0.40 in (2009) |
| September 30 | 79.0°F (2025) | 37.0°F (2017) | 1.64 in (2011) |