Westerly weather in September

In September, Westerly sees average daytime highs of 72°F and overnight lows near 59°F, with 3.8 in of rain across 8.8 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 75°F in the first days to 68°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 Westerly's 2nd-clearest and 9th-windiest month. For the whole year in context, see Westerly's year-round climate.

Daytime high
72°
4th warmest
Overnight low
59°
9th coldest
Rainfall
3.8 in
8.8 wet days
Daylight
12 h 18 min
5:33 AM – 5:50 PM
Cloud cover
54%
2nd clearest
Wind
7 mph
9th windiest
Solar energy
4.31 kWh/m²
Travel score
6.9
out of 10

Westerly is town in Washington County, Rhode Island, United States.

Founded
1661

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 75°F in the first days to 68°F by the end.

A typical September day in Westerly reaches about 72°F in the afternoon and slips back to 59°F overnight — a 13°F spread between the day's warmth and the night's chill. On most days the high lands between 65°F and 79°F. Set against its neighbours, September runs about 6°F cooler than August and about 10°F warmer than October.

40°50°60°70°80°151015202530
Avg high (°F)Avg low (°F)
17663
27663
37663
47563
57562
67562
77462
87462
97461
107461
117361
127360
137360
147260
157259
167259
177159
187158
197158
207158
217058
227057
236957
246957
256956
266956
276856
286855
296755
306755

How September really feels in Westerly

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.

Westerly weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan37° / 25°3.71059.40.0
Feb39° / 26°3.28.94.510.30.0
Mar45° / 33°4.310.63.811.71.0
Apr55° / 42°3.810.60.713.13.4
May64° / 51°3.310.8014.35.6
Jun73° / 60°3.610.1014.96.6
Jul80° / 67°3.110.3014.76.5
Aug78° / 66°3.99.8013.76.8
Sep72° / 59°3.88.8012.36.9
Oct62° / 49°4.29.20.110.95.4
Nov51° / 39°3.790.59.72.7
Dec43° / 31°4.510.43.29.10.5

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 16% of September, with mostly cloudy or overcast conditions the remaining 47%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15446
25446
35446
45446
55446
65446
75446
85446
95446
105446
115446
125446
135446
145446
155347
165347
175248
185248
195347
205248
215248
225149
235149
245149
255149
265248
275248
285248
295347
305347

Chance of precipitation in September

Any precipitation

Westerly gets around 3.8 in of rain over 8.8 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 29% and peaks near 33% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
126
226
327
427
527
627
727
828
928
1028
1128
1228
1328
1428
1527
1628
1728
1828
1928
2029
2129
2230
2330
2431
2531
2632
2732
2832
2933
3033

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 36% 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 (%)
1182627209
2192726208
3202726198
4212726198
5222726187
6232725187
7252625186
8262625176
9272624175
10292524175
11302524174
12322423174
13332423164
14352422163
15362422163
16372421152
17392420152
18402420152
19412419142
20422419141
21432418141
22452417131
23462417121
24472416121
25492316111
26502316101
2751231691
2853231581
2954221581
3056221570

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.

0246810151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237light breeze
247light 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 5:18 AM to 5:48 AM, and sunset from 6:16 PM to 5:25 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:186:16
212.95:196:14
312.95:206:13
412.85:216:11
512.85:226:09
612.75:236:08
712.75:246:06
812.65:256:04
912.65:266:02
1012.65:276:01
1112.55:285:59
1212.55:295:57
1312.45:305:55
1412.45:315:53
1512.35:325:52
1612.35:335:50
1712.25:355:48
1812.25:365:46
1912.15:375:44
2012.15:385:43
2112.05:395:41
2212.05:405:39
2311.95:415:37
2411.95:425:35
2511.85:435:34
2611.85:445:32
2711.85:455:30
2811.75:465:28
2911.75:475:27
3011.65:485:25

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.31 kWh/m².

For context, solar energy here swings from a low near 1.68 kWh/m² to a high of 6.16 kWh/m² in June across the year — September's 4.31 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.9Bright
34.8Bright
44.8Bright
54.8Bright
64.7Bright
74.7Bright
84.6Bright
94.6Bright
104.5Bright
114.5Bright
124.5Bright
134.4Bright
144.4Bright
154.4Bright
164.3Bright
174.3Bright
184.2Bright
194.2Bright
204.2Bright
214.1Bright
224.1Bright
234.0Bright
244.0Moderate
253.9Moderate
263.9Moderate
273.8Moderate
283.8Moderate
293.7Moderate
303.7Moderate
Planning a trip in September

Hazard calendar for Westerly

In seasonPeak

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

Westerly 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 Westerly?

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
4.8
Beach & pool
4th-best month of the year

September is a reasonable time to visit Westerly for sightseeing.

What to pack for Westerly in September

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

In September, Westerly sees daytime highs around 72°F and nights near 59°F. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

Sea temperature near Westerly in September

The nearest coast averages about 67°F in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 11 mi away) is warmest in August at about 69°F and coldest in February near 39°F.

It's comfortable for a long swim from Jul 29 to Aug 30 — about 1.1 months when the water holds above 68°F.

40°50°60°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarm
Sea temperature (°F)Comfort
Jan43Bracing
Feb39Bracing
Mar40Bracing
Apr44Bracing
May51Bracing
Jun60Cool
Jul67Cool
Aug69Refreshing
Sep67Cool
Oct62Cool
Nov55Bracing
Dec48Bracing

UV index in Westerly 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 Westerly peaks around July 10 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 22 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 10UV 8Dec 22UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May8Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Westerly 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 Westerly is worst in July — around 15 µg/m³ PM2.5 (moderate), about 2.6× the cleanest month (November, 6 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1515 µg/m³Nov 206 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb10Good
Mar11Good
Apr12Good
May14Moderate
Jun14Moderate
Jul15Moderate
Aug13Moderate
Sep10Good
Oct7Good
Nov6Good
Dec6Good
Location & terrain

Where is Westerly?

Westerly sits at 41.4°N, 71.8°W, 36 ft above sea level, in United States. The nearest listed city is Ledyard, 11 mi away.

Topography around Westerly

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

Within 2 miles, the terrain around Westerly has only modest variations in elevation — a maximum elevation change of 282 ft around an average of 89 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 574 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,325 ft.

The land around Westerly is covered by trees (65%) within 2 miles, trees (56%) and water (33%) within 10 miles, and trees (48%) and water (45%) within 50 miles.

2 miles
282 ft
10 miles
574 ft
50 miles
1,325 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Ledyard 11 mi · New London 14 mi · Waterford 16 mi · Norwich 16 mi · South Kingstown 16 mi · Montville Center 18 mi · Narragansett 21 mi · Plainfield 21 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 Westerly (41.3776°, -71.8273°, elevation 36 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).