Pekin weather in September

In September, Pekin sees average daytime highs of 77°F and overnight lows near 57°F, with 3.1 in of rain across 7.5 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 81°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 Pekin's 1st-clearest and 9th-windiest month. For the whole year in context, see Pekin's year-round climate.

Daytime high
77°
4th warmest
Overnight low
57°
9th coldest
Rainfall
3.1 in
7.5 wet days
Daylight
12 h 18 min
5:45 AM – 6:01 PM
Cloud cover
46%
1st clearest
Wind
7 mph
9th windiest
Solar energy
4.67 kWh/m²
Travel score
7.3
out of 10

Pekin is city and county seat of Tazewell County, Illinois, United States.

Density
832/km²
people per km²
Founded
1829

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 81°F in the first days to 73°F by the end.

A typical September day in Pekin reaches about 77°F in the afternoon and slips back to 57°F overnight — a 20°F spread between the day's warmth and the night's chill. On most days the high lands between 66°F and 88°F. Set against its neighbours, September runs about 6°F cooler than August and about 13°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18263
28162
38162
48162
58161
68061
78060
88060
97960
107959
117959
127858
137858
147858
157757
167757
177756
187656
197656
207655
217555
227554
237454
247453
257453
267353
277352
287352
297252
307251

How September really feels in Pekin

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.

Pekin weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan34° / 20°2.18.34.89.40.0
Feb39° / 23°2.17.13.910.40.1
Mar51° / 33°3.010.11.711.72.4
Apr63° / 43°4.511.40.5135.1
May73° / 54°4.613014.26.2
Jun82° / 64°4.611.7014.86.0
Jul84° / 67°3.710.2014.65.5
Aug83° / 65°3.18.9013.66.2
Sep77° / 57°3.17.5012.37.3
Oct64° / 45°3.18.60.110.96.0
Nov50° / 34°2.98.119.72.4
Dec39° / 25°2.37.53.19.20.1

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 13% of September, with mostly cloudy or overcast conditions the remaining 40%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16337
26337
36337
46337
56436
66337
76337
86337
96238
106238
116139
126139
136040
145941
155941
165941
175842
185842
195743
205743
215743
225743
235743
245743
255743
265743
275743
285644
295644
305743

Chance of precipitation in September

Any precipitation

Pekin gets around 3.1 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 26% and peaks near 28% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
126
226
326
426
526
626
726
826
927
1027
1127
1228
1328
1428
1528
1628
1728
1828
1927
2027
2126
2226
2325
2425
2525
2625
2724
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 44% of days. Sticky, muggy-or-worse air turns up on roughly 17% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
11722252511
21823252410
3202325239
4222425228
5242425207
6252524196
7272524185
8292623175
9312622174
10332622164
11352521153
12372520153
13392520152
14412419142
15432418142
16452317132
17472316131
18492215121
19512115121
20532114111
21552013111
22591912100
2361181290
2463181180
2564171180
2666161170
2768161060
2869151060
2970151050
3071141050

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.

0246810151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247light 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 5:30 AM to 5:59 AM, and sunset from 6:27 PM to 5:36 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:306:27
212.95:316:25
312.95:326:23
412.85:336:22
512.85:346:20
612.75:356:18
712.75:366:16
812.65:376:15
912.65:386:13
1012.55:396:11
1112.55:406:10
1212.45:416:08
1312.45:426:06
1412.45:436:04
1512.35:446:03
1612.35:456:01
1712.25:465:59
1812.25:475:57
1912.15:485:56
2012.15:495:54
2112.05:505:52
2212.05:515:50
2311.95:525:49
2411.95:535:47
2511.95:545:45
2611.85:555:43
2711.85:565:42
2811.75:575:40
2911.75:585:38
3011.65:595:36

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 1.77 kWh/m² to a high of 6.4 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
254.2Bright
264.2Bright
274.2Bright
284.1Bright
294.1Bright
304.0Bright
Planning a trip in September

Is September a good time to visit Pekin?

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
6.4
Beach & pool
4th-best month of the year

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

What to pack for Pekin in September

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

In September, Pekin sees daytime highs around 77°F and nights near 57°F. Worth packing: light clothes and sun protection. About 8 days see rain.

light clothessun protection

UV index in Pekin 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 Pekin peaks around June 20 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJun 20UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Pekin 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 Pekin 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 1916 µg/m³Oct 228 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar13Moderate
Apr11Good
May14Moderate
Jun13Moderate
Jul16Moderate
Aug15Moderate
Sep12Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Pekin?

Pekin sits at 40.6°N, 89.6°W, 502 ft above sea level, in United States. The nearest listed city is East Peoria, 7.5 mi away.

Topography around Pekin

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

Within 2 miles, the terrain around Pekin has only modest variations in elevation — a maximum elevation change of 243 ft around an average of 509 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 384 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 535 ft.

The land around Pekin is covered by trees (32%) and artificial surfaces (26%) within 2 miles, cropland (49%) and trees (30%) within 10 miles, and cropland (74%) within 50 miles.

2 miles
243 ft
10 miles
384 ft
50 miles
535 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: East Peoria 7.5 mi · Peoria 9.3 mi · Morton 9.9 mi · North Peoria 11 mi · Washington 16 mi · Normal 34 mi · Bloomington 34 mi · Galesburg 47 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 Pekin (40.5675°, -89.6407°, elevation 502 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).