Chillicothe weather in September

In September, Chillicothe sees average daytime highs of 78°F and overnight lows near 58°F, with 3.0 in of rain across 8.2 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 10th-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 40% 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 Chillicothe's 1st-clearest and 10th-windiest month. For the whole year in context, see Chillicothe's year-round climate.

Daytime high
78°
4th warmest
Overnight low
58°
9th coldest
Rainfall
3.0 in
8.2 wet days
Daylight
12 h 18 min
6:19 AM – 6:34 PM
Cloud cover
51%
1st clearest
Wind
5 mph
10th windiest
Solar energy
4.5 kWh/m²
Travel score
7.1
out of 10

Chillicothe is city in and the county seat of Ross County, Ohio, United States.

Density
792/km²
people per km²
Founded
1803

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 Chillicothe reaches about 78°F in the afternoon and slips back to 58°F overnight — a 20°F spread between the day's warmth and the night's chill. On most days the high lands between 68°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)
18263
28263
38263
48262
58162
68162
78161
88061
98060
108060
117960
127959
137959
147859
157858
167858
177757
187757
197757
207656
217656
227656
237555
247555
257454
267454
277454
287353
297353
307353

How September really feels in Chillicothe

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.

Chillicothe weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan39° / 25°3.310.54.49.50.0
Feb42° / 27°3.19.6410.50.4
Mar52° / 35°4.111.2211.72.7
Apr64° / 45°4.312.40.4135.3
May73° / 55°4.513014.16.2
Jun81° / 64°4.012.2014.75.9
Jul85° / 67°3.712014.55.2
Aug84° / 65°2.99.9013.55.7
Sep78° / 58°3.08.2012.37.1
Oct66° / 47°2.98.70.1116.1
Nov53° / 37°3.19.20.79.83.1
Dec43° / 30°3.410.22.69.30.5

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 40% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 43%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15941
25941
36040
46040
55941
65941
75941
85941
95842
105842
115842
125842
135743
145644
155644
165644
175644
185545
195545
205545
215545
225545
235545
245644
255644
265644
275644
285644
295743
305743

Chance of precipitation in September

Any precipitation

Chillicothe gets around 3.0 in of rain over 8.2 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 27% and peaks near 29% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
129
229
329
428
528
628
727
827
926
1026
1126
1226
1326
1426
1526
1626
1726
1826
1926
2027
2127
2227
2327
2427
2527
2627
2727
2827
2926
3026

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 40% of days. Sticky, muggy-or-worse air turns up on roughly 18% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
11724212611
21824212611
31925212510
4202521249
5222621238
6232621227
7252621216
8272621206
9282621195
10302621184
11312622174
12332622163
13352522163
14362521152
15382521142
16402421132
17422420122
18442420121
19462319111
20472318101
2149231891
2251221791
2353221681
2454211681
2557211570
2659201470
2761191460
2862191360
2963181360
3064181350

Wind in September

Winds average 5 mph in September.

Across September, daily wind ranges from about 5 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

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 6:05 AM to 6:32 AM, and sunset from 6:59 PM to 6:10 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.96:056:59
212.96:056:57
312.86:066:56
412.86:076:54
512.76:086:52
612.76:096:51
712.66:106:49
812.66:116:47
912.66:126:46
1012.56:136:44
1112.56:146:42
1212.46:156:41
1312.46:166:39
1412.36:176:37
1512.36:186:36
1612.36:196:34
1712.26:206:32
1812.26:216:30
1912.16:226:29
2012.16:226:27
2112.06:236:25
2212.06:246:24
2311.96:256:22
2411.96:266:20
2511.96:276:19
2611.86:286:17
2711.86:296:15
2811.76:306:14
2911.76:316:12
3011.66:326:10

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.5 kWh/m².

For context, solar energy here swings from a low near 1.68 kWh/m² to a high of 6.18 kWh/m² in June across the year — September's 4.5 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.1Bright
25.0Bright
35.0Bright
45.0Bright
54.9Bright
64.9Bright
74.8Bright
84.8Bright
94.8Bright
104.7Bright
114.7Bright
124.7Bright
134.6Bright
144.6Bright
154.5Bright
164.5Bright
174.5Bright
184.4Bright
194.4Bright
204.3Bright
214.3Bright
224.3Bright
234.2Bright
244.2Bright
254.1Bright
264.1Bright
274.0Bright
284.0Bright
294.0Moderate
304.0Moderate
Planning a trip in September

Is September a good time to visit Chillicothe?

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

7.1
Sightseeing
1st-best month of the year
6.5
Beach & pool
3rd-best month of the year

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

What to pack for Chillicothe in September

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

In September, Chillicothe sees daytime highs around 78°F and nights near 58°F. Worth packing: light clothes, rain gear and sun protection. About 8 days see rain.

light clothesrain gearsun protection

UV index in Chillicothe 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 Chillicothe peaks around June 19 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 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJun 19UV 9Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun10Very high
Jul9Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov3Moderate
Dec2Low

Air quality in Chillicothe 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 Chillicothe is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1218 µg/m³Oct 248 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb10Good
Mar10Good
Apr11Good
May14Moderate
Jun17Moderate
Jul18Moderate
Aug15Moderate
Sep12Good
Oct8Good
Nov8Good
Dec8Good
Location & terrain

Where is Chillicothe?

Chillicothe sits at 39.3°N, 83.0°W, 630 ft above sea level, in United States. The nearest listed city is Lancaster, 34 mi away.

Topography around Chillicothe

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

Within 2 miles, the terrain around Chillicothe has only modest variations in elevation — a maximum elevation change of 469 ft around an average of 673 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 778 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 892 ft.

The land around Chillicothe is covered by trees (36%), grassland (28%) and artificial surfaces (25%) within 2 miles, trees (58%) and cropland (22%) within 10 miles, and trees (53%) and cropland (31%) within 50 miles.

2 miles
469 ft
10 miles
778 ft
50 miles
892 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Lancaster 34 mi · Grove City 39 mi · Pickerington 40 mi · Portsmouth 42 mi · Columbus 43 mi · Reynoldsburg 44 mi · Whitehall 44 mi · Upper Arlington 46 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 Chillicothe (39.3331°, -82.9824°, elevation 630 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).