Green Bay, WI weather in September
Green Bay is mild in September, with some rain: highs average 72°F and nights drop to about 50°F. There are about 10 days with rain. A good month for most outdoor plans.
- Normal high
- 72°F
- Normal low
- 50°F
- Wet days
- 10
- 3.2 in total
- Muggy days
- 2
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 76°F | 66°F |
| Normal low | 55°F | 45°F |
| Chance of a wet day | 31% | 34% |
| Sunrise / sunset | 6:14 am / 7:29 pm | 6:48 am / 6:35 pm |
| Daylight | 13.2 h | 11.8 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Central Time).
A typical September day
- 6 am53°Fdew point 51°F
- 9 am63°Fdew point 54°F
- Noon69°Fdew point 53°F
- 3 pm70°Fdew point 53°F
- 6 pm64°Fdew point 54°F
- 9 pm58°Fdew point 53°F
NOAA hourly normals (local standard time) from Green Bay (5 mi away); average wind 7 mph; clear or few clouds in 57% of daytime hours, mostly cloudy or overcast in 35%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F15 of 30
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph5 of 30
- Hot dayshigh 90°F or more0 of 30
- Muggy daysdaily mean dew point 65°F or more2 of 30
- Wet daysat least 0.01 in of rain or melted snow10 of 30
- Notable rainat least 0.10 in6 of 30
- Freezing nightslow 32°F or below1 of 30
- Snow on the groundsnow depth 1 in or more0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 3.2 in; a dry September brings about 2.2 in and a wet one about 4.2 in (25th and 75th percentiles). About 2 days bring half an inch or more, and about 1 an inch or more.
How September varies from year to year
- Warmest September, 1991-20202004: average high 78°F
- Coolest September1993: average high 65°F
- Wettest September2019: 9.4 in
- Driest September2004: 0.5 in
- Highest reading92°F (September 5, 2007)
- Lowest reading28°F (September 23, 1995)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 79°F | 72°F | 58°F |
| Normal low | 58°F | 50°F | 40°F |
| Wet days | 10 | 10 | 10 |
| Comfortable days | 12 | 15 | 7 |
| Daylight | 14.0 h | 12.5 h | 11.0 h |
Highs change by -7°F from August and -14°F into October.
Nearby alternatives in September
- Warmer: Davenport, IA244 mi · high 78°F · 8 wet days
How Green Bay ranks in September
- Normal high332nd warmest of 378 cities; 4th of 5 in Wisconsin
- Wet days297th driest of 378
- Comfortable days82nd most of 342
What to pack for Green Bay in September
- A rain jacket or umbrella – rain on about 10 days
Heating and cooling
September has 169 heating degree days and 47 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Green Bay in September?
The normal high is 72°F and the normal low is 50°F. From 1991 to 2020 the hottest September reading was 92°F (September 5, 2007).
Does it rain a lot in Green Bay in September?
About 10 days in September have at least 0.01 in of precipitation, and the normal total is 3.2 in. The wettest September in 1991-2020 was in 2019 (9.4 in); the driest was in 2004 (0.5 in).
Is September a good time to visit Green Bay?
September ranks 3rd of 12 months on our comfort score for Green Bay (69 out of 100). It has about 15 comfortable days. The best months are May, June and September.
Where the numbers come from
- Temperature, rain, snowfall, snow depth, frost dates, humidity and wind by hour and cloud cover: Green Bay (USW00014898), 4.7 mi WSW of the city center, 682 ft (89 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Austin Straubel International Airport (726450-14898), 6.4 mi WSW of the city center, 684 ft (91 ft higher than the city). Hourly observations, 1991-2020.