Defiance weather in September

In September, Defiance sees average daytime highs of 75°F and overnight lows near 55°F, with 2.5 in of rain across 8.2 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 79°F in the first days to 71°F by the end. The sky is clear or mostly clear about 38% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Defiance's 1st-clearest and 10th-windiest month. For the whole year in context, see Defiance's year-round climate.

Daytime high
75°
4th warmest
Overnight low
55°
9th coldest
Rainfall
2.5 in
8.2 wet days
Daylight
12 h 18 min
6:24 AM – 6:40 PM
Cloud cover
52%
1st clearest
Wind
7 mph
10th windiest
Solar energy
4.42 kWh/m²
Travel score
7.1
out of 10

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

Density
534/km²
people per km²
Founded
1822

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 79°F in the first days to 71°F by the end.

A typical September day in Defiance reaches about 75°F in the afternoon and slips back to 55°F overnight — a 20°F spread between the day's warmth and the night's chill. On most days the high lands between 65°F and 85°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)
18061
27960
37960
47960
57959
67859
77859
87858
97758
107758
117757
127657
137656
147656
157656
167555
177555
187455
197454
207454
217353
227353
237353
247252
257252
267151
277151
287151
297050
307050

How September really feels in Defiance

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.

Defiance 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
Jan33° / 20°2.810.169.40.0
Feb37° / 22°2.38.54.810.30.0
Mar48° / 30°3.210.63.111.71.6
Apr60° / 41°3.9120.713.14.6
May71° / 52°4.113.2014.36.0
Jun80° / 61°3.911.5014.96.3
Jul83° / 65°3.411.1014.75.7
Aug81° / 63°3.49.9013.76.5
Sep75° / 55°2.58.2012.37.1
Oct63° / 44°2.790.110.95.6
Nov49° / 34°3.08.91.39.72.2
Dec38° / 26°2.69.23.99.10.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% 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 45%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15644
25644
35644
45743
55743
65743
75743
85743
95743
105743
115644
125545
135545
145545
155545
165545
175545
185446
195446
205446
215446
225347
235347
245347
255248
265248
275149
285248
295248
305149

Chance of precipitation in September

Any precipitation

Defiance gets around 2.5 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 28% and peaks near 30% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
127
227
327
427
527
627
727
827
927
1027
1127
1227
1327
1427
1527
1627
1727
1827
1927
2027
2127
2228
2328
2428
2529
2629
2730
2830
2930
3030

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 52% of days. Sticky, muggy-or-worse air turns up on roughly 12% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1252523234
2272523224
3282522214
4302522193
5322621183
6342621173
7362520162
8382520152
9402519142
10412419142
11432419131
12452418121
13472318121
14492217111
15502217101
16532116100
1756201590
1857201580
1959191480
2061181470
2163171370
2266161260
2366161260
2468151160
2569151150
2671141050
2772141040
2873131040
2973131040
307512940

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.

051015151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187light breeze
198light breeze
208light breeze
218light breeze
228light breeze
238light breeze
248light breeze
258light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours 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 84 minutes over September. Sunrise moves from 6:08 AM to 6:38 AM, and sunset from 7:06 PM to 6:15 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.06:087:06
212.96:097:04
312.96:107:03
412.86:117:01
512.86:126:59
612.76:136:58
712.76:146:56
812.66:156:54
912.66:166:52
1012.66:176:51
1112.56:186:49
1212.56:196:47
1312.46:206:45
1412.46:226:43
1512.36:236:42
1612.36:246:40
1712.26:256:38
1812.26:266:36
1912.16:276:35
2012.16:286:33
2112.06:296:31
2212.06:306:29
2311.96:316:27
2411.96:326:26
2511.86:336:24
2611.86:346:22
2711.86:356:20
2811.76:366:19
2911.76:376:17
3011.66:386:15

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.42 kWh/m².

For context, solar energy here swings from a low near 1.58 kWh/m² to a high of 6.3 kWh/m² in June across the year — September's 4.42 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.9Bright
34.9Bright
44.8Bright
54.8Bright
64.8Bright
74.7Bright
84.7Bright
94.7Bright
104.6Bright
114.6Bright
124.5Bright
134.5Bright
144.5Bright
154.4Bright
164.4Bright
174.4Bright
184.3Bright
194.3Bright
204.2Bright
214.2Bright
224.2Bright
234.1Bright
244.1Bright
254.0Bright
264.0Moderate
273.9Moderate
283.9Moderate
293.8Moderate
303.8Moderate
Planning a trip in September

Is September a good time to visit Defiance?

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
5.9
Beach & pool
4th-best month of the year

September is one of the better times to visit Defiance for general sightseeing.

What to pack for Defiance in September

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

In September, Defiance sees daytime highs around 75°F and nights near 55°F. Worth packing: light clothes and rain gear. About 8 days see rain.

light clothesrain gear

UV index in Defiance 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 Defiance peaks around June 18 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 18UV 9Dec 21UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov3Moderate
Dec1Low

Air quality in Defiance 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 Defiance is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1316 µg/m³Oct 228 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar14Moderate
Apr13Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug15Moderate
Sep12Moderate
Oct8Good
Nov9Good
Dec10Good
Location & terrain

Where is Defiance?

Defiance sits at 41.3°N, 84.4°W, 676 ft above sea level, in United States. The nearest listed city is Bowling Green, 37 mi away.

Topography around Defiance

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

Within 2 miles, the terrain around Defiance has only modest variations in elevation — a maximum elevation change of 138 ft around an average of 709 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 223 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 781 ft.

The land around Defiance is covered by trees (34%), grassland (23%) and artificial surfaces (20%) within 2 miles, cropland (66%) and trees (20%) within 10 miles, and cropland (73%) within 50 miles.

2 miles
138 ft
10 miles
223 ft
50 miles
781 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Bowling Green 37 mi · New Haven 37 mi · Lima 40 mi · Findlay 40 mi · Fort Wayne 42 mi · Perrysburg 42 mi · Sylvania 45 mi · Adrian 45 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 Defiance (41.2845°, -84.3558°, elevation 676 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).