As of 15:29 CDT

Summit, IL weather in September

84°

Summit, Saturday, 8 August, 15:29

Clear. Feels like 87°. High 85°, low 69°.

Pressure29.97 inHg

Wind8.9 mph W

Humidity58%

Visibility6.2 mi

Dew point66°

See detailed hourly forecast

In September, Summit, IL averages a high of 73.9° and a low of 59.5°. About 3.3 inches of precipitation fall over the month (10 wet days). The record high is 94.3° (2011) and the record low 36.9° (1974). Normals are computed over the last 60 years.

Day	High	Low	Chance of precip.	Record high	Record low
1	78.8°	64.4°	30%	94.3° (2011)	53.6° (1967)
2	79.2°	64.8°	27%	91.8° (2008)	50.7° (1965)
3	79°	64.4°	27%	93.6° (2023)	51.8° (1974)
4	77.7°	63.5°	33%	91.6° (2023)	49.6° (2025)
5	77.7°	63°	27%	90.3° (2023)	52.5° (1974)
6	77.5°	63.1°	38%	91.9° (1990)	49.1° (2025)
7	77.7°	62.6°	32%	92.3° (1960)	48° (2025)
8	75.9°	62.2°	35%	91.4° (1978)	47.1° (2024)
9	75.7°	61.9°	32%	92.8° (2013)	50.9° (1986)
10	76.5°	61.2°	30%	94.3° (2013)	50° (2017)
11	76.1°	61.2°	32%	90.7° (2005)	46.6° (1993)
12	76.1°	61°	30%	90° (2005)	46.9° (2014)
13	75.6°	61°	40%	92.1° (2005)	43.7° (2014)
14	74.3°	60.1°	32%	87.1° (1991)	44.4° (1975)
15	73.2°	59.4°	23%	87.8° (1991)	46.4° (2007)
16	72.7°	59°	25%	87.4° (2024)	47.5° (1966)
17	73.8°	59.4°	38%	88.2° (2018)	47.3° (2014)
18	73.9°	59.2°	32%	87.3° (2025)	48° (1973)
19	73.9°	59.9°	33%	90.7° (2025)	43.2° (2020)
20	73.8°	58.8°	48%	89.8° (2017)	44.4° (1991)
21	72.3°	58.3°	32%	91.4° (2017)	44.6° (1991)
22	70.5°	57.2°	47%	90.7° (2017)	39.7° (1995)
23	69.1°	54.7°	32%	91° (2017)	36.9° (1974)
24	69.6°	55.4°	25%	89.8° (2007)	42.3° (1976)
25	70.2°	55.4°	42%	89.6° (2017)	44.1° (2001)
26	70.2°	55.6°	30%	88° (2017)	44.4° (1984)
27	69.4°	55.4°	28%	85.6° (2021)	42.1° (1991)
28	67.6°	54.9°	25%	83.7° (1971)	43.5° (1975)
29	68.2°	53.4°	30%	88.3° (2025)	37.9° (1967)
30	69.3°	53.8°	17%	85.3° (1971)	37° (1993)