Danville weather in September

In September, Danville sees average daytime highs of 78°F and overnight lows near 57°F, with 2.9 in of rain across 7.5 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 82°F in the first days to 73°F by the end. The sky is clear or mostly clear about 46% 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 Danville's 1st-clearest and 9th-windiest month. For the whole year in context, see Danville's year-round climate.

Daytime high
78°
4th warmest
Overnight low
57°
9th coldest
Rainfall
2.9 in
7.5 wet days
Daylight
12 h 18 min
5:37 AM – 5:53 PM
Cloud cover
47%
1st clearest
Wind
7 mph
9th windiest
Solar energy
4.67 kWh/m²
Travel score
7.3
out of 10

Danville is city in and the county seat of Vermilion County, Illinois, United States.

Density
684/km²
people per km²
Founded
1827

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 73°F by the end.

A typical September day in Danville reaches about 78°F in the afternoon and slips back to 57°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 5°F cooler than August and about 13°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18263
28262
38262
48162
58161
68161
78160
88060
98060
108059
117959
127958
137958
147858
157857
167857
177756
187756
197756
207655
217655
227655
237554
247554
257453
267453
277453
287352
297352
307351

How September really feels in Danville

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.

Danville weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan36° / 21°2.98.94.39.50.0
Feb40° / 24°2.47.53.510.40.2
Mar51° / 33°3.510.61.811.72.5
Apr64° / 44°4.611.90.3135.2
May73° / 54°4.713.2014.26.2
Jun81° / 64°4.412.1014.85.9
Jul84° / 67°3.710.8014.65.6
Aug83° / 65°3.28.8013.66.2
Sep78° / 57°2.97.5012.37.3
Oct65° / 46°3.38.40.110.96.1
Nov51° / 35°3.38.40.79.82.7
Dec40° / 26°2.69.13.49.20.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 46% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 38%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16337
26337
36436
46436
56436
66634
76634
86535
96535
106535
116436
126436
136337
146238
156238
166139
176040
186040
196040
206040
215941
226040
236040
246040
256040
266040
276040
286040
296139
306139

Chance of precipitation in September

Any precipitation

Danville gets around 2.9 in of rain over 7.5 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
1125
1225
1325
1426
1526
1626
1726
1826
1926
2026
2126
2226
2326
2426
2526
2626
2725
2825
2925
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 46% of days. Sticky, muggy-or-worse air turns up on roughly 16% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
12020242511
22221232410
3232123239
4252223228
5272223217
6292323206
7302322196
8322322185
9342322174
10362322164
11382321153
12392321143
13412221142
14432221132
15452120122
16472120111
17492019111
18511919101
19521918101
2056181790
2157181690
2260171580
2362161480
2463161380
2564161280
2666151270
2767151170
2868141170
2969141160
3071131060

Wind in September

Winds average 7 mph in September.

Across September, daily wind ranges from about 7 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207light breeze
218light breeze
228light breeze
238light breeze
248light breeze
258light 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 5:22 AM to 5:51 AM, and sunset from 6:18 PM to 5:29 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:226:18
212.95:236:16
312.85:246:15
412.85:256:13
512.85:266:11
612.75:276:10
712.75:286:08
812.65:296:06
912.65:306:05
1012.55:316:03
1112.55:326:01
1212.45:336:00
1312.45:345:58
1412.45:355:56
1512.35:365:54
1612.35:375:53
1712.25:385:51
1812.25:395:49
1912.15:405:47
2012.15:415:46
2112.05:425:44
2212.05:435:42
2311.95:445:41
2411.95:455:39
2511.95:465:37
2611.85:475:35
2711.85:485:34
2811.75:495:32
2911.75:505:30
3011.65:515:29

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.67 kWh/m².

For context, solar energy here swings from a low near 1.75 kWh/m² to a high of 6.38 kWh/m² in June across the year — September's 4.67 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.2Bright
25.2Bright
35.1Bright
45.1Bright
55.1Bright
65.0Bright
75.0Bright
84.9Bright
94.9Bright
104.9Bright
114.8Bright
124.8Bright
134.7Bright
144.7Bright
154.7Bright
164.6Bright
174.6Bright
184.5Bright
194.5Bright
204.5Bright
214.4Bright
224.4Bright
234.3Bright
244.3Bright
254.3Bright
264.2Bright
274.2Bright
284.2Bright
294.1Bright
304.1Bright
Planning a trip in September

Is September a good time to visit Danville?

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
6.6
Beach & pool
3rd-best month of the year

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

What to pack for Danville in September

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

In September, Danville sees daytime highs around 78°F and nights near 57°F. Worth packing: light clothes and sun protection. About 8 days see rain.

light clothessun protection

UV index in Danville in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Danville peaks around July 11 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 highHighModerateJul 11UV 9Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Danville 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 Danville is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateModerateGoodJul 1516 µg/m³Oct 218 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb13Moderate
Mar12Moderate
Apr12Good
May14Moderate
Jun15Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Danville?

Danville sits at 40.1°N, 87.6°W, 600 ft above sea level, in United States. The nearest listed city is Urbana, 30 mi away.

Topography around Danville

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

Within 2 miles, the terrain around Danville has only modest variations in elevation — a maximum elevation change of 197 ft around an average of 617 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 292 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 545 ft.

The land around Danville is covered by trees (54%), artificial surfaces (22%) and grassland (20%) within 2 miles, cropland (59%) and trees (27%) within 10 miles, and cropland (78%) within 50 miles.

2 miles
197 ft
10 miles
292 ft
50 miles
545 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Urbana 30 mi · Champaign 32 mi · Crawfordsville 40 mi · West Lafayette 43 mi · Lafayette 45 mi · Terre Haute 47 mi · Charleston 52 mi · Mattoon 59 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 Danville (40.1245°, -87.63°, elevation 600 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).