South Suffolk weather in September

In September, South Suffolk sees average daytime highs of 80°F and overnight lows near 65°F, with 4.8 in of rain across 10.9 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 2nd-wettest month of the year here.

Highs ease over the month, from about 84°F in the first days to 77°F by the end. The sky is clear or mostly clear about 34% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 48 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is South Suffolk's 7th-clearest and 9th-windiest month. For the whole year in context, see South Suffolk's year-round climate.

Daytime high
80°
4th warmest
Overnight low
65°
9th coldest
Rainfall
4.8 in
10.9 wet days
Daylight
12 h 12 min
5:54 AM – 6:08 PM
Cloud cover
58%
7th clearest
Wind
7 mph
9th windiest
Solar energy
4.35 kWh/m²
Travel score
6.3
out of 10

South Suffolk is human settlement in United States of America.

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 84°F in the first days to 77°F by the end.

A typical September day in South Suffolk reaches about 80°F in the afternoon and slips back to 65°F overnight — a 16°F spread between the day's warmth and the night's chill. On most days the high lands between 73°F and 88°F. Set against its neighbours, September runs about 5°F cooler than August and about 9°F warmer than October.

50°60°70°80°90°151015202530
Avg high (°F)Avg low (°F)
18469
28468
38468
48368
58368
68367
78367
88267
98267
108266
118266
128166
138165
148165
158165
168065
178064
188064
198064
207964
217963
227963
237863
247862
257862
267862
277762
287761
297761
307660

How September really feels in South Suffolk

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.

South Suffolk weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan50° / 33°3.49.31.39.82.4
Feb53° / 35°3.18.81.210.63.0
Mar60° / 41°3.910.60.511.74.8
Apr69° / 50°3.49.5012.96.5
May77° / 59°3.810.8013.96.7
Jun84° / 67°4.111.7014.55.3
Jul88° / 72°5.014.9014.34.0
Aug86° / 70°4.713.1013.44.7
Sep80° / 65°4.810.9012.26.3
Oct71° / 54°3.77.7011.17.1
Nov61° / 43°3.48.40.1105.5
Dec54° / 37°3.59.50.69.53.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 34% 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 50%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15050
25050
35050
45149
55149
65149
75149
85149
95050
105050
115149
125149
135149
145050
155050
164951
174951
184852
194753
204654
214753
224753
234753
244852
254951
265050
275050
285050
295248
305248

Chance of precipitation in September

Any precipitation

South Suffolk gets around 4.8 in of rain over 10.9 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 35% and peaks near 40% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
140
240
340
440
539
638
738
837
936
1036
1135
1234
1334
1433
1533
1633
1732
1833
1933
2033
2134
2234
2334
2433
2533
2632
2731
2831
2930
3030

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the muggy band about 27% of days. Sticky, muggy-or-worse air turns up on roughly 48% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1282330351
2382329351
3482429341
4492428331
55102428321
66102428311
77112428291
87122428281
98122428271
109132428251
1110132428241
1211142429221
1312142329211
1413152329191
1514152329181
1614152329171
1715162329161
1816162329151
1916162429150
2017172428140
2118172427140
2219172426140
2320172425130
2421172424130
2523182423120
2624182422120
2726182421110
2827182420110
2929182418110
3030182418100

Wind in September

Winds average 7 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
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 48 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 66 minutes over September. Sunrise moves from 5:41 AM to 6:06 AM, and sunset from 6:31 PM to 5:46 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:416:31
212.85:426:29
312.75:436:28
412.75:446:26
512.75:456:25
612.65:466:23
712.65:466:22
812.55:476:20
912.55:486:19
1012.55:496:17
1112.45:506:15
1212.45:506:14
1312.45:516:12
1412.35:526:11
1512.35:536:09
1612.25:546:08
1712.25:556:06
1812.25:556:04
1912.15:566:03
2012.15:576:01
2112.05:586:00
2212.05:595:58
2311.96:005:57
2411.96:005:55
2511.96:015:53
2611.86:025:52
2711.86:035:50
2811.76:045:49
2911.76:055:47
3011.76:065:46

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.35 kWh/m².

For context, solar energy here swings from a low near 2.17 kWh/m² to a high of 6.28 kWh/m² in June across the year — September's 4.35 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
84.7Bright
94.6Bright
104.6Bright
114.5Bright
124.5Bright
134.5Bright
144.4Bright
154.4Bright
164.3Bright
174.3Bright
184.3Bright
194.2Bright
204.2Bright
214.2Bright
224.1Bright
234.1Bright
244.1Bright
254.0Bright
264.0Bright
274.0Moderate
284.0Moderate
294.0Moderate
303.9Moderate
Planning a trip in September

Hazard calendar for South Suffolk

In seasonPeak

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

South Suffolk 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 South Suffolk?

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

6.3
Sightseeing
4th-best month of the year
6.5
Beach & pool
2nd-best month of the year

September is a reasonable time to visit South Suffolk for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for South Suffolk in September

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

In September, South Suffolk sees daytime highs around 80°F and nights near 65°F. Worth packing: light clothes and rain gear. About 11 days see rain.

light clothesrain gear

Sea temperature near South Suffolk in September

The nearest coast averages about 76°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 38 mi away) is warmest in August at about 79°F and coldest in February near 41°F.

It's comfortable for a long swim from Jun 3 to Oct 14 — about 4.4 months when the water holds above 68°F.

40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan44Bracing
Feb41Bracing
Mar45Bracing
Apr54Bracing
May63Cool
Jun72Refreshing
Jul78Warm
Aug79Warm
Sep76Warm
Oct68Cool
Nov57Bracing
Dec49Bracing

UV index in South Suffolk in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in South Suffolk peaks around July 12 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJul 12UV 9Dec 19UV 2
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar5High
Apr7High
May8Very high
Jun9Very high
Jul9Very high
Aug7Very high
Sep7High
Oct4Moderate
Nov3Moderate
Dec2Moderate

Air quality in South Suffolk 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 South Suffolk is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (November, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1216 µg/m³Nov 237 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb9Good
Mar11Good
Apr12Good
May13Moderate
Jun16Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct7Good
Nov7Good
Dec7Good
Location & terrain

Where is South Suffolk?

South Suffolk sits at 36.7°N, 76.6°W, 52 ft above sea level, in United States. The nearest listed city is Suffolk, 0.6 mi away.

Topography around South Suffolk

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

Within 2 miles, the terrain around South Suffolk has only modest variations in elevation — a maximum elevation change of 125 ft around an average of 52 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 167 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 341 ft.

The land around South Suffolk is covered by trees (58%) within 2 miles, trees (71%) within 10 miles, and trees (53%) and water (24%) within 50 miles.

2 miles
125 ft
10 miles
167 ft
50 miles
341 ft
treesgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: Suffolk 0.6 mi · Portsmouth Heights 14 mi · Portsmouth 18 mi · Chesapeake 19 mi · Norfolk 19 mi · Newport News 21 mi · Hampton 25 mi · East Hampton 26 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 South Suffolk (36.7171°, -76.5902°, elevation 52 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).