Rockford, IL weather in September
Rockford is mild in September, with some rain: highs average 75°F and nights drop to about 54°F. There are about 8 days with rain. A good month for most outdoor plans.
- Normal high
- 75°F
- Normal low
- 54°F
- Wet days
- 8
- 3.6 in total
- Muggy days
- 3
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 80°F | 70°F |
| Normal low | 59°F | 48°F |
| Chance of a wet day | 29% | 29% |
| Sunrise / sunset | 6:21 am / 7:30 pm | 6:52 am / 6:40 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 am56°Fdew point 52°F
- 9 am65°Fdew point 55°F
- Noon72°Fdew point 54°F
- 3 pm73°Fdew point 53°F
- 6 pm68°Fdew point 54°F
- 9 pm61°Fdew point 54°F
NOAA hourly normals (local standard time) from Rockford Gtr Rockford Airport (5 mi away); average wind 7 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F14 of 30
- Hot dayshigh 90°F or more2 of 30
- Muggy daysdaily mean dew point 65°F or more3 of 30
- Wet daysat least 0.01 in of rain or melted snow8 of 30
- Notable rainat least 0.10 in5 of 30
- Freezing nightslow 32°F or below0 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 3.6 in; a dry September brings about 1.9 in and a wet one about 5.3 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, 1991-20202005: average high 80°F
- Coolest September1993: average high 68°F
- Wettest September2001: 9.2 in
- Driest September2004: 0.3 in
- Highest reading96°F (September 10, 2013)
- Lowest reading28°F (September 30, 1993)
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 | 82°F | 75°F | 62°F |
| Normal low | 62°F | 54°F | 42°F |
| Wet days | 9 | 8 | 10 |
| Comfortable days | 8 | 14 | 11 |
| Daylight | 13.8 h | 12.5 h | 11.1 h |
Highs change by -7°F from August and -13°F into October.
Nearby alternatives in September
- Cooler: Sister Bay, WI224 mi · high 68°F · 10 wet days
How Rockford ranks in September
- Normal high275th warmest of 378 cities; 8th of 8 in Illinois
- Wet days213th driest of 378
- Comfortable days101st most of 342
What to pack for Rockford in September
- A rain jacket or umbrella – rain on about 8 days
Heating and cooling
September has 107 heating degree days and 89 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Rockford in September?
The normal high is 75°F and the normal low is 54°F. From 1991 to 2020 the hottest September reading was 96°F (most recently on September 10, 2013).
Does it rain a lot in Rockford in September?
About 8 days in September have at least 0.01 in of precipitation, and the normal total is 3.6 in. The wettest September in 1991-2020 was in 2001 (9.2 in); the driest was in 2004 (0.3 in).
Is September a good time to visit Rockford?
September ranks 2nd of 12 months on our comfort score for Rockford (67 out of 100). It has about 14 comfortable days and about 2 days at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall, snow depth, frost dates and humidity and wind by hour: Rockford Gtr Rockford Airport (USW00094822), 5.4 mi S of the city center, 730 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Greater Rockford Airport (725430-94822), 5.4 mi S of the city center, 725 ft . Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).