Seymour weather in September

In September, Seymour sees average daytime highs of 79°F and overnight lows near 59°F, with 2.9 in of rain across 8.1 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 12th-wettest month of the year here.

Highs ease over the month, from about 83°F in the first days to 74°F by the end. The sky is clear or mostly clear about 43% 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 Seymour's 1st-clearest and 9th-windiest month. For the whole year in context, see Seymour's year-round climate.

Daytime high
79°
4th warmest
Overnight low
59°
9th coldest
Rainfall
2.9 in
8.1 wet days
Daylight
12 h 12 min
6:30 AM – 6:45 PM
Cloud cover
49%
1st clearest
Wind
6 mph
9th windiest
Solar energy
4.62 kWh/m²
Travel score
7.0
out of 10

Seymour is city in Indiana, United States.

Density
629/km²
people per km²
Founded
1852

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 83°F in the first days to 74°F by the end.

A typical September day in Seymour reaches about 79°F in the afternoon and slips back to 59°F overnight — a 20°F spread between the day's warmth and the night's chill. On most days the high lands between 69°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)
18364
28364
38364
48263
58263
68263
78262
88162
98161
108161
118061
128060
138060
147959
157959
167959
177858
187858
197857
207757
217756
227656
237656
247655
257555
267555
277554
287454
297453
307453

How September really feels in Seymour

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.

Seymour weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 12th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan39° / 25°3.39.33.49.60.0
Feb43° / 27°3.08.43.410.50.6
Mar53° / 36°4.2111.711.73.0
Apr65° / 46°4.912.50.2135.5
May74° / 56°5.112.7014.16.3
Jun82° / 65°4.211.6014.75.7
Jul86° / 68°3.511.4014.55.0
Aug84° / 66°3.19.3013.55.6
Sep79° / 59°2.98.1012.37.0
Oct66° / 47°3.28.10116.3
Nov53° / 37°3.49.10.89.93.1
Dec43° / 29°3.69.92.99.30.5

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 43% 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 41%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16040
26040
36040
46040
56040
65941
76040
86040
96040
105941
115941
125842
135842
145842
155842
165842
175842
185842
195941
205941
215941
226040
236040
246040
256139
266040
276040
286040
296040
306139

Chance of precipitation in September

Any precipitation

Seymour gets around 2.9 in of rain over 8.1 wet days in September, the driest month. 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 28% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
127
227
327
427
527
627
726
826
926
1026
1126
1226
1326
1426
1526
1627
1727
1827
1928
2028
2128
2228
2328
2428
2528
2627
2727
2826
2926
3025

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 21% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
11521212814
21722212813
31822212712
41922212611
52123212510
6232321249
7252321238
8262321227
9282321216
10302321215
11322321205
12342221194
13352221183
14372221183
15392120173
16412119162
17432119162
18452018152
19472017141
20492017131
21511916131
22531915121
23551914111
24571814101
25581813101
2659181391
2761171291
2862171281
2963161281
3066161170

Wind in September

Winds average 6 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
136calm
146calm
156calm
166calm
176calm
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 6:17 AM to 6:44 AM, and sunset from 7:10 PM to 6:22 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.96:177:10
212.86:177:08
312.86:187:07
412.86:197:05
512.76:207:04
612.76:217:02
712.66:227:00
812.66:236:59
912.66:246:57
1012.56:256:55
1112.56:266:54
1212.46:276:52
1312.46:286:50
1412.36:296:49
1512.36:296:47
1612.26:306:45
1712.26:316:44
1812.26:326:42
1912.16:336:40
2012.16:346:39
2112.06:356:37
2212.06:366:35
2311.96:376:34
2411.96:386:32
2511.96:396:30
2611.86:406:29
2711.86:416:27
2811.76:426:25
2911.76:436:24
3011.66:446:22

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.62 kWh/m².

For context, solar energy here swings from a low near 1.73 kWh/m² to a high of 6.23 kWh/m² in June across the year — September's 4.62 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.1Bright
25.1Bright
35.1Bright
45.0Bright
55.0Bright
65.0Bright
74.9Bright
84.9Bright
94.8Bright
104.8Bright
114.8Bright
124.7Bright
134.7Bright
144.7Bright
154.6Bright
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 Seymour?

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

7.0
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 Seymour for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Seymour in September

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

In September, Seymour sees daytime highs around 79°F and nights near 59°F. Worth packing: light clothes, rain gear and sun protection. About 8 days see rain.

light clothesrain gearsun protection

UV index in Seymour 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 Seymour peaks around June 23 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 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJun 23UV 9Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov3Moderate
Dec2Low

Air quality in Seymour 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 Seymour is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (October, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1316 µg/m³Oct 237 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb11Good
Mar11Good
Apr11Good
May13Moderate
Jun15Moderate
Jul17Moderate
Aug13Moderate
Sep10Good
Oct7Good
Nov7Good
Dec8Good
Location & terrain

Where is Seymour?

Seymour sits at 39.0°N, 85.9°W, 604 ft above sea level, in United States. The nearest listed city is Columbus, 17 mi away.

Topography around Seymour

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

Within 2 miles, the terrain around Seymour has only modest variations in elevation — a maximum elevation change of 98 ft around an average of 587 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 489 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 810 ft.

The land around Seymour is covered by cropland (35%), grassland (25%) and artificial surfaces (22%) within 2 miles, cropland (53%) and trees (32%) within 10 miles, and trees (53%) and cropland (32%) within 50 miles.

2 miles
98 ft
10 miles
489 ft
50 miles
810 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Columbus 17 mi · Bloomington 37 mi · Franklin 37 mi · Shelbyville 39 mi · Clarksville 47 mi · New Albany 47 mi · Greenwood 47 mi · Jeffersonville 48 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 Seymour (38.9592°, -85.8902°, elevation 604 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).