Belleville weather in September: Belleville, Illinois: normal highs, lows, rain and records for September
Belleville in September has a normal high of 83°F and a normal low of 57°F, a daily mean of 70°F, falling from 87°F on the 1st to 79°F by the 30th. Measurable precipitation falls on 7 days in a normal September, 3.35 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 29°C and low of 14°C, 85 mm of precipitation in September.
- NOAA stationBelleville Siu Research
- Station IDUSW00013802
- Location38.52°N 89.85°W
- Elevation450 ft (137 m)
- From the center8 miles
- Population40,560
- Jan 43° 24°
- Feb 49° 28°
- Mar 59° 36°
- Apr 71° 46°
- May 79° 56°
- Jun 87° 65°
- Jul 90° 68°
- Aug 89° 65°
- Sep 83° 57°
- Oct 73° 47°
- Nov 58° 37°
- Dec 46° 28°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Belleville in September?
The normal high is 83°F and the normal low 57°F, for a daily mean of 70.1°F. September is 7.1°F cooler than August and 10.4°F warmer than October. September is the 4th warmest month of the year in Belleville and the 8th wettest. Across the month the normal high falls 8°F, from 87°F on September 1 to 79°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 67°F and 73°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 23%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 87°F | 62°F | 22% | 16% |
| September 8 | 85°F | 60°F | 21% | 15% |
| September 15 | 84°F | 57°F | 22% | 15% |
| September 22 | 82°F | 55°F | 22% | 15% |
| September 30 | 79°F | 52°F | 23% | 15% |
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 | 87°F | 62°F | 22% | 16% | 13 h |
| September 2 | 87°F | 62°F | 22% | 16% | 13 h |
| September 3 | 87°F | 61°F | 21% | 16% | 13 h |
| September 4 | 86°F | 61°F | 21% | 15% | 13 h |
| September 5 | 86°F | 61°F | 21% | 15% | 12 h 50 min |
| September 6 | 86°F | 60°F | 21% | 15% | 12 h 50 min |
| September 7 | 86°F | 60°F | 21% | 15% | 12 h 50 min |
| September 8 | 85°F | 60°F | 21% | 15% | 12 h 50 min |
| September 9 | 85°F | 59°F | 21% | 15% | 12 h 40 min |
| September 10 | 85°F | 59°F | 21% | 15% | 12 h 40 min |
| September 11 | 85°F | 59°F | 21% | 15% | 12 h 40 min |
| September 12 | 84°F | 58°F | 21% | 15% | 12 h 40 min |
| September 13 | 84°F | 58°F | 21% | 15% | 12 h 30 min |
| September 14 | 84°F | 58°F | 21% | 15% | 12 h 30 min |
| September 15 | 84°F | 57°F | 22% | 15% | 12 h 30 min |
| September 16 | 83°F | 57°F | 22% | 15% | 12 h 30 min |
| September 17 | 83°F | 56°F | 22% | 15% | 12 h 20 min |
| September 18 | 83°F | 56°F | 22% | 15% | 12 h 20 min |
| September 19 | 83°F | 56°F | 22% | 15% | 12 h 20 min |
| September 20 | 82°F | 55°F | 22% | 15% | 12 h 20 min |
| September 21 | 82°F | 55°F | 22% | 15% | 12 h 20 min |
| September 22 | 82°F | 55°F | 22% | 15% | 12 h 10 min |
| September 23 | 81°F | 54°F | 22% | 15% | 12 h 10 min |
| September 24 | 81°F | 54°F | 22% | 15% | 12 h 10 min |
| September 25 | 81°F | 54°F | 23% | 15% | 12 h 10 min |
| September 26 | 80°F | 53°F | 23% | 15% | 12 h |
| September 27 | 80°F | 53°F | 23% | 15% | 12 h |
| September 28 | 80°F | 53°F | 23% | 15% | 12 h |
| September 29 | 79°F | 52°F | 23% | 15% | 12 h |
| September 30 | 79°F | 52°F | 23% | 15% | 11 h 50 min |
- Normal high
- 83°FSeptember average
- Normal low
- 57°FSeptember average
- Precipitation
- 3.35 inmonth total
- Days with precipitation
- 70.01 inch or more
- Days at 90°F or more
- 7
- Daylight
- 13 h to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 29
- Days at 80°F or more
- 21
- Sunshine
- 81%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00013802; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Belleville in September?
On a given September day the chance of 0.01 inch or more is 22% on average, highest around September 30 (23%). In all, 3.35 in falls on 7 days of a normal September, 1 of them with an inch or more.
In a normal September in Belleville, 7 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00013802.
How humid and windy is Belleville in September?
At 3 p.m. the normal temperature is 75°F with 44% relative humidity and a dew point of 52°F; at 6 a.m. it is 54°F with 91% humidity. The wind averages 5.8 mph, most often from the west-southwest in the afternoon.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 54°F | 51°F | 91% | 3.7 mph | 65% |
| 9 a.m. | 65°F | 54°F | 68% | 7.3 mph | 62% |
| noon | 73°F | 53°F | 49% | 9.0 mph | 60% |
| 3 p.m. | 75°F | 52°F | 44% | 9.0 mph | 63% |
| 6 p.m. | 67°F | 54°F | 62% | 5.1 mph | 68% |
| 9 p.m. | 60°F | 54°F | 78% | 4.1 mph | 73% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00013802. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for September in Belleville?
The warmest September temperature on this station's record (since 1948) is 103°F, on September 5, 1954; the coldest is 26°F, on September 23, 1995. The wettest September brought 9.49 in (2005).
The September mean against the 1991-2020 normal of 70.1°F: 2021 70.3°F (+0.3), 2022 67.9°F (−2.2), 2023 69.0°F (−1.1), 2024 69.4°F (−0.7), 2025 72.9°F (+2.8), 2026 78.0°F (+7.9). 3 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 70.3°F | +0.3°F | 2.94 in |
| 2022 | 67.9°F | −2.2°F | 2.23 in |
| 2023 | 69.0°F | −1.1°F | 1.16 in |
| 2024 | 69.4°F | −0.7°F | – |
| 2025 | 72.9°F | +2.8°F | – |
| 2026 | 78.0°F | +7.9°F | – |
Source: records: ACIS, station USW00013802; recent months: ACIS, station USW00013802. Records and recent months use complete months only.
How does September in Belleville compare across Illinois?
Across the 144 places PlainClimate covers in Illinois, September normal highs run from 72°F in Barrington to 84°F in Anna; Belleville's is 83°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.