New Castle weather in September

In September, New Castle sees average daytime highs of 76°F and overnight lows near 56°F, with 2.9 in of rain across 7.9 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 71°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 New Castle's 1st-clearest and 10th-windiest month. For the whole year in context, see New Castle's year-round climate.

Daytime high
76°
4th warmest
Overnight low
56°
9th coldest
Rainfall
2.9 in
7.9 wet days
Daylight
12 h 18 min
6:28 AM – 6:44 PM
Cloud cover
50%
1st clearest
Wind
7 mph
10th windiest
Solar energy
4.55 kWh/m²
Travel score
7.2
out of 10

New Castle is city in Indiana, United States.

Density
930/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 80°F in the first days to 71°F by the end.

A typical September day in New Castle reaches about 76°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 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)
18062
28062
38061
47961
57961
67960
77860
87860
97859
107859
117758
127758
137758
147657
157657
167656
177556
187556
197555
207455
217454
227454
237354
247353
257353
267253
277252
287152
297151
307151

How September really feels in New Castle

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 Castle 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
Jan35° / 21°3.29.85.39.50.0
Feb38° / 24°2.68.84.610.40.0
Mar49° / 32°3.810.92.711.72.0
Apr62° / 43°4.712.50.7134.8
May71° / 53°4.613.6014.26.0
Jun79° / 63°4.212.2014.86.2
Jul82° / 66°3.411.4014.56.1
Aug81° / 64°3.09.8013.66.6
Sep76° / 56°2.97.9012.37.2
Oct63° / 45°3.28.80.210.95.7
Nov50° / 35°3.48.71.19.82.3
Dec39° / 26°3.210.33.99.20.1

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 42%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15743
25743
35842
45842
55941
65941
75941
85941
95941
106040
115941
125941
136040
145941
155941
165941
175941
185842
195842
205842
215941
225842
235842
245842
255743
265743
275644
285644
295644
305644

Chance of precipitation in September

Any precipitation

New Castle gets around 2.9 in of rain over 7.9 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 27% and peaks near 28% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
128
228
328
427
527
627
726
826
926
1026
1126
1226
1326
1426
1526
1626
1727
1827
1927
2027
2127
2228
2328
2428
2528
2628
2728
2827
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 14% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1252124247
2262123236
3282223225
4292222225
5312322214
6332321204
7352321183
8362320173
9382420172
10392419162
11412419151
12422418141
13442418141
14462417131
15472316130
16492316120
17522215110
18542214100
19552114100
2058201390
2160201280
2262191180
2363181180
2465181070
2566171070
266817960
276916960
286916960
297215850
307215850

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
197light 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 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 6:13 AM to 6:42 AM, and sunset from 7:09 PM to 6:20 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.96:137:09
212.96:147:07
312.86:157:06
412.86:167:04
512.76:177:02
612.76:187:01
712.76:196:59
812.66:206:57
912.66:216:56
1012.56:226:54
1112.56:236:52
1212.46:246:50
1312.46:256:49
1412.36:266:47
1512.36:276:45
1612.36:286:44
1712.26:296:42
1812.26:306:40
1912.16:316:38
2012.16:326:37
2112.06:336:35
2212.06:346:33
2311.96:356:32
2411.96:366:30
2511.96:376:28
2611.86:386:26
2711.86:396:25
2811.76:406:23
2911.76:416:21
3011.66:426:20

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.55 kWh/m².

For context, solar energy here swings from a low near 1.7 kWh/m² to a high of 6.27 kWh/m² in July across the year — September's 4.55 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
234.3Bright
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 New Castle?

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
6.1
Beach & pool
4th-best month of the year

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

What to pack for New Castle in September

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

In September, New Castle sees daytime highs around 76°F and nights near 56°F. Worth packing: light clothes and sun protection. About 8 days see rain.

light clothessun protection

UV index in New Castle 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 Castle 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 New Castle 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 Castle 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 1317 µg/m³Oct 228 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb12Good
Mar12Good
Apr12Good
May14Moderate
Jun16Moderate
Jul17Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is New Castle?

New Castle sits at 39.9°N, 85.4°W, 1,063 ft above sea level, in United States. The nearest listed city is Muncie, 18 mi away.

Topography around New Castle

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

Within 2 miles, the terrain around New Castle has only modest variations in elevation — a maximum elevation change of 187 ft around an average of 1,050 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 338 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 860 ft.

The land around New Castle is covered by trees (38%), cropland (22%) and grassland (21%) within 2 miles, cropland (68%) within 10 miles, and cropland (69%) and trees (20%) within 50 miles.

2 miles
187 ft
10 miles
338 ft
50 miles
860 ft
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Muncie 18 mi · Anderson 21 mi · Greenfield 24 mi · Richmond 26 mi · Fishers 34 mi · Noblesville 35 mi · Lawrence 35 mi · Shelbyville 35 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 Castle (39.9289°, -85.3702°, elevation 1,063 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).