Wilton weather in September

In September, Wilton sees average daytime highs of 74°F and overnight lows near 59°F, with 3.9 in of rain across 9.4 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 78°F in the first days to 69°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 Wilton's 2nd-clearest and 9th-windiest month. For the whole year in context, see Wilton's year-round climate.

Daytime high
74°
4th warmest
Overnight low
59°
9th coldest
Rainfall
3.9 in
9.4 wet days
Daylight
12 h 18 min
5:40 AM – 5:56 PM
Cloud cover
55%
2nd clearest
Wind
6 mph
9th windiest
Solar energy
4.23 kWh/m²
Travel score
6.9
out of 10

Wilton is town in Fairfield County, Connecticut, United States.

Founded
1802

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 78°F in the first days to 69°F by the end.

A typical September day in Wilton reaches about 74°F in the afternoon and slips back to 59°F overnight — a 15°F spread between the day's warmth and the night's chill. On most days the high lands between 65°F and 82°F. Set against its neighbours, September runs about 7°F cooler than August and about 11°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17864
27863
37863
47863
57763
67762
77762
87662
97661
107661
117661
127560
137560
147460
157459
167459
177358
187358
197358
207258
217257
227257
237156
247156
257156
267055
277055
286955
296954
306954

How September really feels in Wilton

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.

Wilton weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan37° / 24°3.49.35.39.40.0
Feb39° / 25°3.18.84.410.30.0
Mar47° / 32°4.210.53.711.71.4
Apr58° / 42°3.810.80.613.14.2
May68° / 52°3.511.3014.36.0
Jun78° / 62°3.911.1014.96.5
Jul83° / 67°3.710.9014.75.7
Aug81° / 66°4.110.4013.66.4
Sep74° / 59°3.99.4012.36.9
Oct62° / 48°4.18.80.110.95.5
Nov51° / 38°3.38.50.79.72.7
Dec42° / 30°4.210.13.59.10.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 47%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15248
25248
35248
45248
55248
65248
75347
85347
95347
105446
115446
125545
135545
145446
155545
165446
175446
185347
195446
205347
215347
225248
235149
245149
255149
265149
275149
285248
295248
305248

Chance of precipitation in September

Any precipitation

Wilton gets around 3.9 in of rain over 9.4 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 30% and peaks near 31% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
128
228
329
429
530
630
730
831
931
1031
1131
1231
1331
1431
1530
1630
1730
1830
1930
2030
2130
2230
2330
2430
2530
2630
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 41% of days. Sticky, muggy-or-worse air turns up on roughly 18% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1232326208
2242325198
3252324198
4262424188
5272423188
6282423187
7292422177
8302422177
9322421176
10332421166
11342420165
12362420165
13372319165
14392319154
15402318154
16422218153
17432218143
18452217142
19462217132
20482116132
21492116132
22512016121
23532015111
24532015111
25551915101
2656191591
2758191490
2859191480
2961181470
3062181370

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
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm

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 5:24 AM to 5:55 AM, and sunset from 6:22 PM to 5:31 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:246:22
212.95:266:21
312.95:276:19
412.85:286:17
512.85:296:16
612.75:306:14
712.75:316:12
812.65:326:10
912.65:336:09
1012.65:346:07
1112.55:356:05
1212.55:366:03
1312.45:376:02
1412.45:386:00
1512.35:395:58
1612.35:405:56
1712.25:415:54
1812.25:425:53
1912.15:435:51
2012.15:445:49
2112.05:455:47
2212.05:465:46
2311.95:475:44
2411.95:485:42
2511.85:495:40
2611.85:505:38
2711.85:515:37
2811.75:535:35
2911.75:545:33
3011.65:555:31

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.23 kWh/m².

For context, solar energy here swings from a low near 1.7 kWh/m² to a high of 6.05 kWh/m² in June across the year — September's 4.23 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.8Bright
34.8Bright
44.7Bright
54.7Bright
64.6Bright
74.6Bright
84.5Bright
94.5Bright
104.5Bright
114.4Bright
124.4Bright
134.3Bright
144.3Bright
154.3Bright
164.2Bright
174.2Bright
184.2Bright
194.1Bright
204.1Bright
214.0Bright
224.0Moderate
233.9Moderate
243.9Moderate
253.8Moderate
263.8Moderate
273.8Moderate
283.7Moderate
293.7Moderate
303.6Moderate
Planning a trip in September

Hazard calendar for Wilton

In seasonPeak

In September, Wilton sits inside its atlantic hurricane season. The full year is below, with each hazard's peak months called out.

Wilton sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Wilton?

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

6.9
Sightseeing
1st-best month of the year
5.4
Beach & pool
4th-best month of the year

September is a reasonable time to visit Wilton for sightseeing.

What to pack for Wilton in September

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

In September, Wilton sees daytime highs around 74°F and nights near 59°F. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

Sea temperature near Wilton in September

The nearest coast averages about 71°F in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in August at about 74°F and coldest in February near 35°F.

It's comfortable for a long swim from Jun 30 to Sep 30 — about 3.1 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan39Bracing
Feb35Bracing
Mar37Bracing
Apr44Bracing
May55Bracing
Jun65Cool
Jul72Refreshing
Aug74Refreshing
Sep71Refreshing
Oct64Cool
Nov55Bracing
Dec46Bracing

UV index in Wilton 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 Wilton peaks around July 11 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 23 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 highHighModerateLowJul 11UV 8Dec 23UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Wilton 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 Wilton is worst in July — around 20 µg/m³ PM2.5 (moderate), about 1.7× the cleanest month (November, 11 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateJul 1220 µg/m³Nov 1612 µg/m³
PM2.5 (µg/m³)Level
Jan13Moderate
Feb16Moderate
Mar17Moderate
Apr17Moderate
May18Moderate
Jun19Moderate
Jul20Moderate
Aug17Moderate
Sep16Moderate
Oct13Moderate
Nov11Good
Dec13Moderate
Location & terrain

Where is Wilton?

Wilton sits at 41.2°N, 73.4°W, 249 ft above sea level, in United States. The nearest listed city is New Canaan, 4.3 mi away.

Topography around Wilton

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

Within 2 miles, the terrain around Wilton has only modest variations in elevation — a maximum elevation change of 440 ft around an average of 344 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,024 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,913 ft.

The land around Wilton is covered by trees (87%) within 2 miles, trees (83%) within 10 miles, and trees (61%) and water (24%) within 50 miles.

2 miles
440 ft
10 miles
1,024 ft
50 miles
1,913 ft
treesgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: New Canaan 4.3 mi · Westport 5.6 mi · Norwalk 5.6 mi · East Norwalk 6.8 mi · North Stamford 6.8 mi · Darien 8.1 mi · Fairfield 9.9 mi · Stamford 11 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 Wilton (41.1954°, -73.4379°, elevation 249 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).