Vandalia weather in September

In September, Vandalia sees average daytime highs of 76°F and overnight lows near 57°F, with 2.7 in of rain across 7.8 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 11th-wettest month of the year here.

Highs ease over the month, from about 80°F in the first days to 72°F by the end. The sky is clear or mostly clear about 41% 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 Vandalia's 1st-clearest and 10th-windiest month. For the whole year in context, see Vandalia's year-round climate.

Daytime high
76°
4th warmest
Overnight low
57°
9th coldest
Rainfall
2.7 in
7.8 wet days
Daylight
12 h 18 min
6:23 AM – 6:39 PM
Cloud cover
51%
1st clearest
Wind
7 mph
10th windiest
Solar energy
4.54 kWh/m²
Travel score
7.2
out of 10

Vandalia is city in Montgomery County, Ohio, United States.

Density
470/km²
people per km²
Founded
1838

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 80°F in the first days to 72°F by the end.

A typical September day in Vandalia reaches about 76°F in the afternoon and slips back to 57°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 66°F and 86°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)
18162
28062
38061
48061
58061
67960
77960
87960
97859
107859
117858
127858
137758
147757
157757
167656
177656
187656
197555
207555
217455
227454
237454
247353
257353
267353
277252
287252
297151
307151

How September really feels in Vandalia

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.

Vandalia weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan36° / 22°3.19.94.99.50.0
Feb39° / 24°2.594.310.40.1
Mar50° / 32°3.711.12.211.72.1
Apr62° / 43°4.512.50.6134.9
May71° / 53°4.413.1014.26.1
Jun80° / 62°3.911.7014.86.2
Jul83° / 66°3.211.4014.55.7
Aug82° / 64°3.19.4013.66.5
Sep76° / 57°2.77.8012.37.2
Oct64° / 45°2.98.10.210.95.8
Nov51° / 35°3.38.91.19.82.5
Dec40° / 27°3.29.73.39.20.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 41% 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
35941
45941
55941
65941
75941
85941
95941
105842
115842
125743
135743
145743
155644
165644
175644
185644
195644
205644
215644
225644
235743
245743
255743
265842
275842
285743
295743
305743

Chance of precipitation in September

Any precipitation

Vandalia gets around 2.7 in of rain over 7.8 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
525
625
725
824
924
1024
1124
1224
1325
1425
1525
1626
1726
1827
1927
2027
2128
2228
2328
2428
2528
2628
2728
2828
2927
3027

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 49% of days. Sticky, muggy-or-worse air turns up on roughly 15% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1242223257
2252322246
3272322236
4282321225
5302420215
6322420204
7342419184
8362419173
9382419163
10402418162
11412418152
12432417142
13452417141
14462316131
15482316121
16502215121
17522214111
18542114101
1957201390
2058201390
2161191280
2261191280
2364181170
2464181170
2566171160
2667171060
2767171060
2869161050
297016950
307115950

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
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287light breeze
297light 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 6:09 AM to 6:37 AM, and sunset from 7:04 PM to 6:15 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.96:097:04
212.96:107:03
312.86:117:01
412.86:126:59
512.76:136:58
612.76:146:56
712.76:156:54
812.66:166:53
912.66:176:51
1012.56:186:49
1112.56:196:47
1212.46:196:46
1312.46:206:44
1412.36:216:42
1512.36:226:41
1612.36:236:39
1712.26:246:37
1812.26:256:35
1912.16:266:34
2012.16:276:32
2112.06:286:30
2212.06:296:29
2311.96:306:27
2411.96:316:25
2511.96:326:23
2611.86:336:22
2711.86:346:20
2811.76:356:18
2911.76:366:17
3011.66:376:15

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.54 kWh/m².

For context, solar energy here swings from a low near 1.64 kWh/m² to a high of 6.24 kWh/m² in June across the year — September's 4.54 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.1Bright
25.0Bright
35.0Bright
45.0Bright
54.9Bright
64.9Bright
74.9Bright
84.8Bright
94.8Bright
104.8Bright
114.7Bright
124.7Bright
134.7Bright
144.6Bright
154.6Bright
164.5Bright
174.5Bright
184.5Bright
194.4Bright
204.4Bright
214.3Bright
224.3Bright
234.2Bright
244.2Bright
254.2Bright
264.1Bright
274.1Bright
284.0Bright
294.0Moderate
303.9Moderate
Planning a trip in September

Is September a good time to visit Vandalia?

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

7.2
Sightseeing
1st-best month of the year
6.2
Beach & pool
4th-best month of the year

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

What to pack for Vandalia in September

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

In September, Vandalia sees daytime highs around 76°F and nights near 57°F. Worth packing: light clothes and sun protection. About 8 days see rain.

light clothessun protection

UV index in Vandalia 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 Vandalia peaks around June 20 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 highHighModerateLowJun 20UV 9Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun10Very high
Jul9Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov3Moderate
Dec2Low

Air quality in Vandalia 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 Vandalia is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1117 µg/m³Oct 238 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb12Good
Mar12Good
Apr12Moderate
May15Moderate
Jun17Moderate
Jul17Moderate
Aug15Moderate
Sep12Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Vandalia?

Vandalia sits at 39.9°N, 84.2°W, 994 ft above sea level, in United States. The nearest listed city is Huber Heights, 5.0 mi away.

Topography around Vandalia

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

Within 2 miles, the terrain around Vandalia has only modest variations in elevation — a maximum elevation change of 308 ft around an average of 968 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 407 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,040 ft.

The land around Vandalia is covered by trees (32%), grassland (32%) and artificial surfaces (28%) within 2 miles, trees (33%), cropland (29%) and grassland (24%) within 10 miles, and cropland (63%) and trees (21%) within 50 miles.

2 miles
308 ft
10 miles
407 ft
50 miles
1,040 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Huber Heights 5.0 mi · Riverside 8.7 mi · Trotwood 8.7 mi · Dayton 9.3 mi · Troy 11 mi · Fairborn 11 mi · Kettering 14 mi · Beavercreek 14 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 Vandalia (39.8906°, -84.1988°, elevation 994 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).