Yarmouth weather in September

In September, Yarmouth sees average daytime highs of 66°F and overnight lows near 62°F, with 4.0 in of rain across 8.3 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 69°F in the first days to 64°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 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 Yarmouth's 2nd-clearest and 9th-windiest month. For the whole year in context, see Yarmouth's year-round climate.

Daytime high
66°
3rd warmest
Overnight low
62°
10th coldest
Rainfall
4.0 in
8.3 wet days
Daylight
12 h 18 min
5:27 AM – 5:44 PM
Cloud cover
51%
2nd clearest
Wind
13 mph
9th windiest
Solar energy
4.45 kWh/m²
Travel score
6.5
out of 10

Yarmouth is town in Massachusetts, United States.

Density
345/km²
people per km²
Founded
1639

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 69°F in the first days to 64°F by the end.

A typical September day in Yarmouth reaches about 66°F in the afternoon and slips back to 62°F overnight — a 4°F spread between the day's warmth and the night's chill. On most days the high lands between 62°F and 71°F. Set against its neighbours, September runs about 5°F cooler than August and about 8°F warmer than October.

50°60°70°80°151015202530
Avg high (°F)Avg low (°F)
16965
26965
36965
46965
56965
66864
76864
86864
96864
106864
116763
126763
136763
146763
156762
166662
176662
186662
196662
206561
216561
226561
236561
246560
256460
266460
276459
286459
296459
306358

How September really feels in Yarmouth

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.

Yarmouth weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan38° / 30°4.311.24.79.30.0
Feb38° / 30°3.8104.710.30.0
Mar41° / 34°4.811.23.711.70.1
Apr47° / 42°4.311.30.613.11.5
May55° / 50°3.610.3014.33.5
Jun64° / 60°3.28.20155.9
Jul71° / 67°2.57.7014.77.0
Aug71° / 67°3.17.8013.77.1
Sep66° / 62°4.08.3012.36.5
Oct59° / 54°4.810.1010.94.6
Nov51° / 44°4.4100.39.62.4
Dec43° / 36°5.1122.890.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 42% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 45%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15842
25743
35743
45644
55644
65644
75644
85644
95644
105644
115545
125545
135545
145545
155545
165644
175644
185644
195545
205545
215545
225446
235446
245446
255446
265446
275446
285446
295545
305545

Chance of precipitation in September

Any precipitation

Yarmouth gets around 4.0 in of rain over 8.3 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 33% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
124
224
325
425
525
625
725
825
925
1025
1125
1225
1325
1426
1526
1626
1727
1827
1928
2028
2129
2230
2330
2431
2531
2632
2732
2833
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 31% of days. Sticky, muggy-or-worse air turns up on roughly 15% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1122435263
2132435253
3142535242
4152534232
5172534222
6182534202
7202633192
8212633182
9222633172
10242632172
11252632161
12262632151
13282631141
14292631131
15302630131
16322630121
17332629110
18342629110
19352628100
20362628100
21372627100
2238262690
2340262590
2441272480
2543272370
2644272270
2746272160
2847272060
2949271950
3051261850

Wind in September

Winds average 13 mph in September.

Across September, daily wind ranges from about 12 mph on the calmest days to 14 mph at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (mph)Feels
112light breeze
212light breeze
312light breeze
412light breeze
512light breeze
612light breeze
712breezy
812breezy
912breezy
1012breezy
1113breezy
1213breezy
1313breezy
1413breezy
1513breezy
1613breezy
1713breezy
1813breezy
1913breezy
2013breezy
2113breezy
2213breezy
2313breezy
2413breezy
2513breezy
2613breezy
2713breezy
2813breezy
2914breezy
3014breezy

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 5:11 AM to 5:42 AM, and sunset from 6:10 PM to 5:18 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:116:10
212.95:126:08
312.95:136:07
412.85:146:05
512.85:156:03
612.85:166:01
712.75:176:00
812.75:195:58
912.65:205:56
1012.65:215:54
1112.55:225:53
1212.55:235:51
1312.45:245:49
1412.45:255:47
1512.35:265:45
1612.35:275:44
1712.25:285:42
1812.25:295:40
1912.15:305:38
2012.15:315:36
2112.05:325:34
2212.05:335:33
2311.95:345:31
2411.95:365:29
2511.85:375:27
2611.85:385:25
2711.75:395:24
2811.75:405:22
2911.75:415:20
3011.65:425:18

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.45 kWh/m².

For context, solar energy here swings from a low near 1.58 kWh/m² to a high of 6.41 kWh/m² in July across the year — September's 4.45 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.2Bright
25.1Bright
35.1Bright
45.0Bright
55.0Bright
64.9Bright
74.9Bright
84.8Bright
94.8Bright
104.7Bright
114.7Bright
124.6Bright
134.6Bright
144.5Bright
154.5Bright
164.5Bright
174.4Bright
184.3Bright
194.3Bright
204.3Bright
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

Hazard calendar for Yarmouth

In seasonPeak

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

Yarmouth 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 Yarmouth?

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

6.5
Sightseeing
3rd-best month of the year
2.9
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Yarmouth for sightseeing.

What to pack for Yarmouth in September

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

In September, Yarmouth sees daytime highs around 66°F and nights near 62°F. Worth packing: rain gear and a windbreaker. About 8 days see rain.

rain geara windbreaker

Sea temperature near Yarmouth in September

The nearest coast averages about 65°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 68°F and coldest in February near 38°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

30°40°50°60°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarm
Sea temperature (°F)Comfort
Jan40Bracing
Feb38Bracing
Mar38Bracing
Apr43Bracing
May50Bracing
Jun59Bracing
Jul66Cool
Aug68Refreshing
Sep65Cool
Oct58Bracing
Nov51Bracing
Dec45Bracing

UV index in Yarmouth 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 Yarmouth peaks around June 21 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 highHighModerateLowJun 21UV 8Dec 23UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr5High
May7Very high
Jun8Very high
Jul8Very high
Aug5Moderate
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low
Location & terrain

Where is Yarmouth?

Yarmouth sits at 41.7°N, 70.2°W, 33 ft above sea level, in United States. The nearest listed city is Barnstable, 3.7 mi away.

Topography around Yarmouth

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

Within 2 miles, the terrain around Yarmouth has only modest variations in elevation — a maximum elevation change of 151 ft around an average of 46 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 253 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 630 ft.

The land around Yarmouth is covered by trees (60%) within 2 miles, water (61%) and trees (30%) within 10 miles, and water (75%) and trees (21%) within 50 miles.

2 miles
151 ft
10 miles
253 ft
50 miles
630 ft
treesgrasslandartificial surfaceswaterwetland
September weather nearby: Barnstable 3.7 mi · Provincetown 24 mi · Duxbury 32 mi · Fairhaven 35 mi · New Bedford 37 mi · Middleborough 37 mi · Hanover 41 mi · Rockland 46 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 Yarmouth (41.7057°, -70.2286°, elevation 33 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).