Springfield weather in September

In September, Springfield sees average daytime highs of 78°F and overnight lows near 58°F, with 3.2 in of rain across 7.4 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 82°F in the first days to 74°F by the end. The sky is clear or mostly clear about 48% of the time in September, and the air most often feels dry.

Daylight stretches from about 12 h 54 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Springfield's 1st-clearest and 9th-windiest month. For the whole year in context, see Springfield's year-round climate.

Daytime high
78°
4th warmest
Overnight low
58°
9th coldest
Rainfall
3.2 in
7.4 wet days
Daylight
12 h 18 min
5:45 AM – 6:01 PM
Cloud cover
45%
1st clearest
Wind
7 mph
9th windiest
Solar energy
4.72 kWh/m²
Travel score
7.3
out of 10

Springfield is capital city of the U.S. state of Illinois and county seat of Sangamon County.

Density
665/km²
people per km²
Founded
1821

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 82°F in the first days to 74°F by the end.

A typical September day in Springfield reaches about 78°F in the afternoon and slips back to 58°F overnight — a 21°F spread between the day's warmth and the night's chill. On most days the high lands between 67°F and 88°F. Set against its neighbours, September runs about 6°F cooler than August and about 12°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18363
28263
38262
48262
58262
68161
78161
88161
98060
108060
118059
127959
137958
147958
157858
167857
177857
187756
197756
207656
217655
227655
237555
247554
257554
267453
277453
287453
297352
307352

How September really feels in Springfield

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Springfield weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan36° / 21°2.483.99.50.0
Feb40° / 24°2.27.53.510.40.2
Mar52° / 34°3.110.11.611.72.7
Apr64° / 44°4.611.90.4135.3
May74° / 55°4.613.4014.26.2
Jun82° / 65°4.311.4014.85.8
Jul85° / 68°3.610.1014.55.4
Aug84° / 65°3.19.4013.65.8
Sep78° / 58°3.27.4012.37.3
Oct66° / 46°3.38.50.110.96.2
Nov52° / 35°3.38.30.99.82.8
Dec40° / 26°2.382.89.20.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 48% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 38%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16436
26436
36535
46535
56535
66436
76436
86436
96436
106337
116337
126238
136139
146139
155941
165941
175941
185842
195842
205941
216040
226040
236040
246139
256139
266238
276238
286238
296238
306238

Chance of precipitation in September

Any precipitation

Springfield gets around 3.2 in of rain over 7.4 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 25% and peaks near 26% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
126
226
325
425
525
625
725
825
925
1025
1126
1226
1326
1426
1526
1626
1726
1826
1926
2026
2126
2226
2325
2425
2525
2625
2725
2824
2924
3024

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 43% of days. Sticky, muggy-or-worse air turns up on roughly 19% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
11620242713
21821242612
31921242511
4212223249
5232223238
6252323227
7272322217
8292422206
9302421195
10322421185
11342420184
12362320174
13372320173
14392319163
15412219153
16432218152
17452217142
18472117132
19492116131
20522015121
21531915121
22551914111
23581813101
24591812101
2561171291
2663171190
2765161180
2866161080
2968151070
306915970

Wind in September

Winds average 7 mph in September.

Across September, daily wind ranges from about 6 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
16calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 54 min at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 78 minutes over September. Sunrise moves from 5:31 AM to 5:59 AM, and sunset from 6:26 PM to 5:37 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:316:26
212.95:326:24
312.85:336:23
412.85:346:21
512.75:356:19
612.75:366:18
712.75:366:16
812.65:376:14
912.65:386:13
1012.55:396:11
1112.55:406:09
1212.45:416:07
1312.45:426:06
1412.35:436:04
1512.35:446:02
1612.35:456:01
1712.25:465:59
1812.25:475:57
1912.15:485:55
2012.15:495:54
2112.05:505:52
2212.05:515:50
2311.95:525:49
2411.95:535:47
2511.95:545:45
2611.85:555:44
2711.85:565:42
2811.75:575:40
2911.75:585:38
3011.65:595:37

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.72 kWh/m².

For context, solar energy here swings from a low near 1.82 kWh/m² to a high of 6.44 kWh/m² in June across the year — September's 4.72 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.2Bright
25.2Bright
35.2Bright
45.1Bright
55.1Bright
65.0Bright
75.0Bright
85.0Bright
94.9Bright
104.9Bright
114.8Bright
124.8Bright
134.8Bright
144.7Bright
154.7Bright
164.7Bright
174.6Bright
184.6Bright
194.5Bright
204.5Bright
214.5Bright
224.4Bright
234.4Bright
244.4Bright
254.3Bright
264.3Bright
274.3Bright
284.2Bright
294.2Bright
304.1Bright
Planning a trip in September

Is September a good time to visit Springfield?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.3
Sightseeing
1st-best month of the year
6.7
Beach & pool
3rd-best month of the year

September is one of the better times to visit Springfield for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Springfield in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Springfield sees daytime highs around 78°F and nights near 58°F. Worth packing: light clothes and sun protection. About 7 days see rain.

light clothessun protection

UV index in Springfield in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Springfield peaks around June 21 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJun 21UV 9Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Springfield in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Springfield is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 8 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodModerateGoodJul 1716 µg/m³Oct 238 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb13Moderate
Mar12Moderate
Apr11Good
May14Moderate
Jun14Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Springfield?

Springfield sits at 39.8°N, 89.6°W, 597 ft above sea level, in United States. The nearest listed city is Jacksonville, 32 mi away.

Topography around Springfield

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Springfield.

Within 2 miles, the terrain around Springfield has only modest variations in elevation — a maximum elevation change of 121 ft around an average of 604 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 194 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 390 ft.

The land around Springfield is covered by trees (44%) and artificial surfaces (43%) within 2 miles, cropland (45%) and trees (31%) within 10 miles, and cropland (77%) within 50 miles.

2 miles
121 ft
10 miles
194 ft
50 miles
390 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Jacksonville 32 mi · Decatur 37 mi · Pekin 53 mi · Morton 57 mi · Bloomington 58 mi · East Peoria 60 mi · Normal 60 mi · Peoria 62 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Springfield (39.8017°, -89.6437°, elevation 597 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).