New Haven weather in September

In September, New Haven sees average daytime highs of 75°F and overnight lows near 56°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 39% 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 New Haven's 1st-clearest and 10th-windiest month. For the whole year in context, see New Haven's year-round climate.

Daytime high
75°
4th warmest
Overnight low
56°
9th coldest
Rainfall
2.5 in
8.2 wet days
Daylight
12 h 18 min
6:26 AM – 6:42 PM
Cloud cover
52%
1st clearest
Wind
7 mph
10th windiest
Solar energy
4.47 kWh/m²
Travel score
7.1
out of 10

New Haven is city in Indiana.

Density
614/km²
people per km²
Founded
1839

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 New Haven reaches about 75°F in the afternoon and slips back to 56°F overnight — a 19°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
57960
67859
77859
87858
97758
107758
117757
127657
137657
147656
157656
167555
177555
187455
197454
207454
217353
227353
237353
247252
257252
267151
277151
287151
297050
307050

How September really feels in New Haven

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.

New Haven 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°2.810.25.99.40.0
Feb37° / 23°2.38.24.710.40.0
Mar48° / 31°3.310.63.111.71.7
Apr61° / 41°4.012.10.613.14.6
May71° / 52°4.113.1014.36.0
Jun80° / 62°4.012014.96.2
Jul83° / 65°3.411.1014.75.8
Aug81° / 63°3.410.1013.66.5
Sep75° / 56°2.58.2012.37.1
Oct63° / 45°2.990.210.95.6
Nov49° / 35°3.19.31.49.72.1
Dec38° / 26°2.79.74.19.10.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 39% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 45%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15842
25842
35842
45842
55941
65842
75842
85743
95743
105743
115743
125545
135545
145545
155446
165446
175446
185446
195347
205347
215347
225347
235248
245248
255149
265149
275149
285149
295149
305149

Chance of precipitation in September

Any precipitation

New Haven 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 29% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
127
227
327
427
527
627
726
826
926
1026
1126
1226
1327
1427
1527
1628
1728
1828
1928
2028
2129
2229
2329
2429
2529
2629
2729
2829
2929
3028

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 51% of days. Sticky, muggy-or-worse air turns up on roughly 13% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1252422245
2262421235
3282521224
4302520214
5322520203
6342520193
7362519182
8372519172
9392518162
10412518151
11432418141
12442417131
13462317131
14482317120
15512216110
16522116110
17552015100
1857191590
1959191480
2061181380
2163171370
2265161270
2367161160
2468151160
2569151060
2671141050
2772131050
287313950
297512940
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
187calm
197calm
207light 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 6:11 AM to 6:41 AM, and sunset from 7:09 PM to 6:18 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.06:117:09
212.96:127:07
312.96:137:05
412.86:147:04
512.86:157:02
612.76:167:00
712.76:176:58
812.66:186:57
912.66:196:55
1012.56:206:53
1112.56:216:51
1212.56:226:50
1312.46:236:48
1412.46:246:46
1512.36:256:44
1612.36:266:42
1712.26:276:41
1812.26:286:39
1912.16:296:37
2012.16:306:35
2112.06:316:34
2212.06:336:32
2311.96:346:30
2411.96:356:28
2511.86:366:27
2611.86:376:25
2711.86:386:23
2811.76:396:21
2911.76:406:20
3011.66:416:18

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.47 kWh/m².

For context, solar energy here swings from a low near 1.61 kWh/m² to a high of 6.29 kWh/m² in June across the year — September's 4.47 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
15.0Bright
25.0Bright
34.9Bright
44.9Bright
54.8Bright
64.8Bright
74.8Bright
84.7Bright
94.7Bright
104.7Bright
114.6Bright
124.6Bright
134.6Bright
144.5Bright
154.5Bright
164.5Bright
174.4Bright
184.4Bright
194.3Bright
204.3Bright
214.3Bright
224.2Bright
234.2Bright
244.1Bright
254.1Bright
264.0Bright
274.0Moderate
283.9Moderate
293.9Moderate
303.8Moderate
Planning a trip in September

Is September a good time to visit New Haven?

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 New Haven for general sightseeing.

What to pack for New Haven in September

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

In September, New Haven sees daytime highs around 75°F and nights near 56°F. Worth packing: light clothes and rain gear. About 8 days see rain.

light clothesrain gear

UV index in New Haven 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 New Haven peaks around June 19 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJun 19UV 9Dec 20UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov3Moderate
Dec1Low

Air quality in New Haven 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 New Haven is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1416 µg/m³Oct 228 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb13Moderate
Mar13Moderate
Apr13Moderate
May14Moderate
Jun16Moderate
Jul16Moderate
Aug15Moderate
Sep12Good
Oct8Good
Nov9Good
Dec9Good
Location & terrain

Where is New Haven?

New Haven sits at 41.1°N, 85.0°W, 758 ft above sea level, in United States. The nearest listed city is Fort Wayne, 7.5 mi away.

Topography around New Haven

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

Within 2 miles, the terrain around New Haven has only modest variations in elevation — a maximum elevation change of 135 ft around an average of 768 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 351 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 643 ft.

The land around New Haven is covered by trees (28%), cropland (28%) and grassland (24%) within 2 miles, cropland (49%) and trees (23%) within 10 miles, and cropland (72%) within 50 miles.

2 miles
135 ft
10 miles
351 ft
50 miles
643 ft
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Fort Wayne 7.5 mi · Huntington 29 mi · Defiance 37 mi · Marion 49 mi · Lima 53 mi · Goshen 55 mi · Muncie 63 mi · Elkhart 65 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 New Haven (41.0706°, -85.0144°, elevation 758 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).