Dayton weather in September

In September, Dayton 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 12th-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 42% 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 Dayton's 1st-clearest and 10th-windiest month. For the whole year in context, see Dayton'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
50%
1st clearest
Wind
6 mph
10th windiest
Solar energy
4.56 kWh/m²
Travel score
7.2
out of 10

Dayton is city and county seat of Montgomery County, Ohio, United States.

Density
926/km²
people per km²
Founded
1796

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 Dayton 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
28162
38062
48062
58061
68061
77960
87960
97960
107859
117859
127858
137758
147758
157757
167657
177656
187656
197556
207555
217555
227455
237454
247354
257353
267353
277253
287252
297152
307151

How September really feels in Dayton

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.

Dayton 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
Jan37° / 23°3.29.84.69.50.0
Feb40° / 25°2.79.24.110.40.2
Mar50° / 33°3.911.12.311.72.2
Apr63° / 44°4.612.70.5135.0
May72° / 54°4.613.3014.26.1
Jun80° / 63°4.212.6014.86.0
Jul83° / 66°3.411.6014.55.6
Aug82° / 65°3.210.1013.66.3
Sep76° / 57°2.77.8012.37.2
Oct64° / 46°2.98.40.210.95.9
Nov51° / 36°3.2919.82.6
Dec41° / 28°3.49.73.39.20.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 42% 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 43%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15941
25941
36040
46040
56040
66040
76040
85941
95941
105941
115842
125842
135842
145743
155644
165644
175644
185644
195644
205644
215644
225644
235644
245743
255743
265644
275644
285644
295644
305644

Chance of precipitation in September

Any precipitation

Dayton gets around 2.7 in of rain over 7.8 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 26% and peaks near 27% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
127
227
327
426
526
626
726
825
925
1025
1125
1226
1326
1426
1526
1627
1727
1827
1927
2027
2127
2227
2327
2427
2527
2626
2726
2826
2925
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 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 (%)
1202323258
2222423248
3232422247
4252522236
5272521226
6282520215
7302620204
8322619194
9342619183
10362618173
11372618172
12392618162
13412517151
14432517141
15452417141
16472316131
17492316121
18512215111
19542115100
20552015100
2157201490
2259191480
2361181380
2462181370
2564171270
2665171260
2766161260
2867161160
2969151150
3069151150

Wind in September

Winds average 6 mph in September.

Across September, daily wind ranges from about 6 mph on the calmest days to 7 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
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm

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
212.96:107:02
312.86:117:01
412.86:126:59
512.76:136:57
612.76:146:56
712.76:156:54
812.66:166:52
912.66:176:51
1012.56:186:49
1112.56:196:47
1212.46:206:46
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 4.56 kWh/m².

For context, solar energy here swings from a low near 1.64 kWh/m² to a high of 6.22 kWh/m² in June across the year — September's 4.56 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.1Bright
25.1Bright
35.0Bright
45.0Bright
55.0Bright
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
234.3Bright
244.2Bright
254.2Bright
264.1Bright
274.1Bright
284.0Bright
294.0Bright
304.0Moderate
Planning a trip in September

Is September a good time to visit Dayton?

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
3rd-best month of the year

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

What to pack for Dayton in September

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

In September, Dayton 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 Dayton 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 Dayton 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 highHighModerateJun 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 Dayton 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 Dayton 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 Dayton?

Dayton sits at 39.8°N, 84.2°W, 738 ft above sea level, in United States. The nearest listed city is Riverside, 3.7 mi away.

Topography around Dayton

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

Within 2 miles, the terrain around Dayton has only modest variations in elevation — a maximum elevation change of 207 ft around an average of 764 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 430 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,089 ft.

The land around Dayton is covered by artificial surfaces (55%) and trees (20%) within 2 miles, trees (42%), grassland (26%) and artificial surfaces (20%) within 10 miles, and cropland (59%) and trees (25%) within 50 miles.

2 miles
207 ft
10 miles
430 ft
50 miles
1,089 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Riverside 3.7 mi · Kettering 5.0 mi · Huber Heights 6.8 mi · Trotwood 6.8 mi · Beavercreek 7.5 mi · Vandalia 9.3 mi · Centerville 9.3 mi · Miamisburg 9.3 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 Dayton (39.7589°, -84.1916°, elevation 738 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).