Summerville weather in September

In September, Summerville sees average daytime highs of 84°F and overnight lows near 68°F, with 4.9 in of rain across 12.6 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 86°F in the first days to 81°F by the end. The sky is clear or mostly clear about 33% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 42 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Summerville's 8th-clearest and 9th-windiest month. For the whole year in context, see Summerville's year-round climate.

Daytime high
84°
4th warmest
Overnight low
68°
9th coldest
Rainfall
4.9 in
12.6 wet days
Daylight
12 h 12 min
6:09 AM – 6:21 PM
Cloud cover
57%
8th clearest
Wind
6 mph
9th windiest
Solar energy
4.65 kWh/m²
Travel score
5.3
out of 10

Summerville is town in South Carolina, United States.

Density
974/km²
people per km²
Founded
1847

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 86°F in the first days to 81°F by the end.

A typical September day in Summerville reaches about 84°F in the afternoon and slips back to 68°F overnight — a 16°F spread between the day's warmth and the night's chill. On most days the high lands between 77°F and 90°F. Set against its neighbours, September runs about 4°F cooler than August and about 8°F warmer than October.

50°60°70°80°90°151015202530
Avg high (°F)Avg low (°F)
18771
28771
38671
48671
58670
68670
78670
88670
98569
108569
118569
128569
138569
148568
158468
168468
178468
188467
198367
208367
218367
228366
238366
248266
258265
268265
278265
288165
298164
308164

How September really feels in Summerville

Once humidity and wind are folded in, September averages 8 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
8
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Summerville weather by month

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

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan59° / 39°3.28.810.14.8
Feb62° / 42°3.28.110.85.5
Mar69° / 48°3.48.811.76.7
Apr76° / 55°3.17.912.87.3
May82° / 64°3.210.313.76.1
Jun87° / 71°5.816.914.13.8
Jul90° / 74°6.119143.1
Aug88° / 73°6.61913.23.5
Sep84° / 68°4.912.612.25.3
Oct76° / 57°3.77.611.27.3
Nov68° / 47°2.56.610.37.0
Dec61° / 42°3.47.99.95.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 33% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 19% of September, with mostly cloudy or overcast conditions the remaining 48%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14951
25050
35050
45050
55149
65149
75248
85248
95347
105347
115347
125347
135446
145446
155446
165446
175248
185248
195248
205149
215149
225149
235149
245149
255149
265149
275248
285248
295149
305149

Chance of precipitation in September

Any precipitation

Summerville gets around 4.9 in of rain over 12.6 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 42% and peaks near 51% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
151
250
349
448
547
647
746
845
944
1044
1143
1243
1342
1442
1541
1641
1741
1840
1940
2040
2139
2239
2338
2438
2537
2636
2736
2835
2934
3034

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the oppressive band about 42% of days. Sticky, muggy-or-worse air turns up on roughly 73% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1037225810
203723589
314824558
414825548
515925537
615926536
7161027506
8161127495
9171128485
10271228475
11281228454
12281328444
13291328434
14391428423
153101428423
163101528413
173101528403
184101628403
194101628392
205111627392
216111627382
227111727372
238111727361
249121727351
2510121827331
2611121826321
2712121826311
2813121926291
2914121926281
3015131926261

Wind in September

Winds average 6 mph in September.

Across September, daily wind ranges from about 5 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
15calm
25calm
35calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 42 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 60 minutes over September. Sunrise moves from 5:59 AM to 6:19 AM, and sunset from 6:42 PM to 6:01 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.75:596:42
212.76:006:41
312.66:006:39
412.66:016:38
512.66:026:36
612.56:026:35
712.56:036:34
812.56:046:32
912.46:046:31
1012.46:056:30
1112.46:066:28
1212.36:066:27
1312.36:076:25
1412.36:086:24
1512.26:086:22
1612.26:096:21
1712.26:106:20
1812.16:106:18
1912.16:116:17
2012.16:126:15
2112.06:126:14
2212.06:136:13
2312.06:146:11
2411.96:146:10
2511.96:156:08
2611.96:166:07
2711.86:176:06
2811.86:176:04
2911.76:186:03
3011.76:196:01

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.65 kWh/m².

For context, solar energy here swings from a low near 2.56 kWh/m² to a high of 6.29 kWh/m² in May across the year — September's 4.65 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
15.0Bright
25.0Bright
35.0Bright
44.9Bright
54.9Bright
64.9Bright
74.9Bright
84.9Bright
94.8Bright
104.8Bright
114.8Bright
124.8Bright
134.7Bright
144.7Bright
154.7Bright
164.7Bright
174.6Bright
184.6Bright
194.6Bright
204.5Bright
214.5Bright
224.5Bright
234.5Bright
244.4Bright
254.4Bright
264.4Bright
274.3Bright
284.3Bright
294.3Bright
304.3Bright
Planning a trip in September

Hazard calendar for Summerville

In seasonPeak

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

Summerville 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 Summerville?

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

5.3
Sightseeing
8th-best month of the year
6.4
Beach & pool
2nd-best month of the year

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

What to pack for Summerville in September

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

In September, Summerville sees daytime highs around 84°F and nights near 68°F. Pack light clothes. Worth having: rain gear and sun protection. About 13 days see rain.

light clothesrain gearsun protection

Sea temperature near Summerville in September

The nearest coast averages about 81°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 27 mi away) is warmest in August at about 83°F and coldest in February near 59°F.

It's comfortable for a long swim from Apr 25 to Nov 14 — about 6.7 months when the water holds above 68°F.

60°70°80°90°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan60Cool
Feb59Cool
Mar61Cool
Apr66Cool
May73Refreshing
Jun80Warm
Jul83Tropical
Aug83Tropical
Sep81Warm
Oct75Refreshing
Nov67Cool
Dec63Cool

UV index in Summerville 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 Summerville peaks around July 13 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJul 13UV 9Dec 19UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May8Very high
Jun9Very high
Jul10Very high
Aug9Very high
Sep7Very high
Oct5High
Nov4Moderate
Dec3Moderate

Air quality in Summerville 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 Summerville is worst in March — around 20 µg/m³ PM2.5 (moderate), about 2.8× the cleanest month (December, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodMar 1819 µg/m³Dec 177 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb12Good
Mar20Moderate
Apr14Moderate
May13Moderate
Jun16Moderate
Jul17Moderate
Aug15Moderate
Sep11Good
Oct8Good
Nov8Good
Dec7Good
Location & terrain

Where is Summerville?

Summerville sits at 33.0°N, 80.2°W, 89 ft above sea level, in United States. The nearest listed city is Goose Creek, 8.7 mi away.

Topography around Summerville

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

Within 2 miles, the terrain around Summerville has only modest variations in elevation — a maximum elevation change of 115 ft around an average of 85 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 161 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 299 ft.

The land around Summerville is covered by trees (74%) within 2 miles, trees (79%) within 10 miles, and trees (62%) and water (24%) within 50 miles.

2 miles
115 ft
10 miles
161 ft
50 miles
299 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Goose Creek 8.7 mi · Hanahan 11 mi · North Charleston 16 mi · Charleston 22 mi · Mount Pleasant 24 mi · Sumter 63 mi · Hilton Head 65 mi · Hilton Head Island 66 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 Summerville (33.0185°, -80.1757°, elevation 89 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).