Sumter weather in August

In August, Sumter sees average daytime highs of 89°F and overnight lows near 73°F, with 4.7 in of rain across 14.5 wet days and about 13.3 hours of daylight. It is the 2nd-warmest and 1st-wettest month of the year here.

Day-to-day highs hold fairly steady near 89°F through the month. The sky is clear or mostly clear about 29% of the time in August, and the air most often feels oppressive.

Daylight stretches from about 13 h 42 min at the start of August to 12 h 48 min by month's end. Set against the rest of the year, August is Sumter's 10th-clearest and 12th-windiest month. For the whole year in context, see Sumter's year-round climate.

Daytime high
89°
2nd warmest
Overnight low
73°
11th coldest
Rainfall
4.7 in
14.5 wet days
Daylight
13 h 18 min
5:47 AM – 7:04 PM
Cloud cover
59%
10th clearest
Wind
6 mph
12th windiest
Solar energy
5.4 kWh/m²
Travel score
3.7
out of 10

Sumter is city in and county seat of Sumter County, South Carolina, United States.

Density
491/km²
people per km²
Founded
1845

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 89°F through the month.

A typical August day in Sumter reaches about 89°F in the afternoon and slips back to 73°F overnight — a 16°F spread between the day's warmth and the night's chill. On most days the high lands between 83°F and 96°F. Set against its neighbours, August runs about 2°F cooler than July and about 5°F warmer than September.

60°70°80°90°100°151015202531
Avg high (°F)Avg low (°F)
19074
29074
39074
49074
59074
69074
79074
89073
99073
108973
118973
128973
138973
148973
158973
168973
178973
188973
198973
208973
218973
228972
238972
248972
258872
268872
278872
288871
298871
308871
318771

How August really feels in Sumter

Once humidity and wind are folded in, August averages 31 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
31
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

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

Sumter weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan56° / 37°3.58.90.5104.1
Feb60° / 40°3.38.60.310.74.9
Mar67° / 46°3.49.40.111.76.4
Apr76° / 54°3.48012.87.2
May82° / 63°3.19.5013.76.2
Jun88° / 71°4.213.2014.24.1
Jul91° / 74°4.715.50143.2
Aug89° / 73°4.714.5013.33.7
Sep84° / 67°4.210012.25.6
Oct75° / 56°3.37.6011.17.4
Nov66° / 45°2.87.2010.26.6
Dec59° / 40°3.78.60.19.84.7

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 29% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 21% of August, with mostly cloudy or overcast conditions the remaining 50%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14852
24951
34951
44852
54951
64852
74951
84951
95050
105050
114951
125050
135050
144951
155050
165050
175050
185149
195149
205149
215149
225149
235149
245149
255248
265149
275149
285248
295149
305149
315149

Chance of precipitation in August

Any precipitation

Sumter gets around 4.7 in of rain over 14.5 wet days in August, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 47% and peaks near 53% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202531
Rain chance (%)
153
252
352
451
551
650
750
849
949
1049
1149
1249
1349
1448
1548
1648
1748
1848
1947
2047
2146
2246
2345
2445
2544
2644
2743
2842
2942
3041
3140

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the oppressive band about 58% of days. Sticky, muggy-or-worse air turns up on roughly 87% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
111621665
211622655
311622655
412622645
512622645
611723635
711723635
811723626
911723626
1011723626
1111723626
1211723626
1311723626
1411823616
1511823616
1611923606
1711924596
1812924586
19121024585
20121025575
21121025575
22131125555
23131126554
24131126554
25141127534
26141227533
27151228513
28151328503
29261328483
30261429473
31271429462

Wind in August

Winds average 6 mph in August, the calmest month.

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

0246810151015202531
Wind speed (mph)Feels
16calm
26calm
36calm
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
316calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 13 h 42 min at the start of August to 12 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 54 minutes over August. Sunrise moves from 5:36 AM to 5:58 AM, and sunset from 7:19 PM to 6:45 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.75:367:19
213.75:377:18
313.75:387:17
413.65:387:16
513.65:397:15
613.65:407:14
713.55:417:13
813.55:417:12
913.55:427:11
1013.55:437:10
1113.45:447:09
1213.45:447:08
1313.45:457:07
1413.35:467:06
1513.35:477:05
1613.35:477:04
1713.25:487:03
1813.25:497:01
1913.25:497:00
2013.15:506:59
2113.15:516:58
2213.15:526:56
2313.05:526:55
2413.05:536:54
2513.05:546:53
2612.95:556:51
2712.95:556:50
2812.95:566:49
2912.85:576:47
3012.85:576:46
3112.85:586:45

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.4 kWh/m².

For context, solar energy here swings from a low near 2.42 kWh/m² to a high of 6.2 kWh/m² in June across the year — August's 5.4 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.7Bright
25.7Bright
35.7Bright
45.7Bright
55.6Bright
65.6Bright
75.6Bright
85.6Bright
95.5Bright
105.5Bright
115.5Bright
125.5Bright
135.5Bright
145.5Bright
155.4Bright
165.4Bright
175.4Bright
185.4Bright
195.4Bright
205.3Bright
215.3Bright
225.3Bright
235.3Bright
245.3Bright
255.2Bright
265.2Bright
275.2Bright
285.2Bright
295.1Bright
305.1Bright
315.1Bright
Planning a trip in August

Is August a good time to visit Sumter?

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

3.7
Sightseeing
11th-best month of the year
5.8
Beach & pool
6th-best month of the year

August is a weaker month for outdoor sightseeing in Sumter.

What to pack for Sumter in August

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

In August, Sumter sees daytime highs around 89°F and nights near 73°F. Pack light clothes and rain gear. Worth having: sun protection. About 15 days see rain.

light clothesrain gearsun protection

UV index in Sumter in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sumter peaks around July 13 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 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 20UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7Very high
Oct5Moderate
Nov4Moderate
Dec3Moderate

Air quality in Sumter in August

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where August falls, not just the annual average.

Air quality in Sumter is worst in March — around 18 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (December, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1518 µg/m³Dec 178 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb11Good
Mar18Moderate
Apr13Moderate
May13Moderate
Jun17Moderate
Jul18Moderate
Aug16Moderate
Sep12Good
Oct9Good
Nov8Good
Dec8Good
Location & terrain

Where is Sumter?

Sumter sits at 33.9°N, 80.3°W, 171 ft above sea level, in United States. The nearest listed city is Florence, 38 mi away.

Topography around Sumter

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

Within 2 miles, the terrain around Sumter has only modest variations in elevation — a maximum elevation change of 98 ft around an average of 171 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 305 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,079 ft.

The land around Sumter is covered by trees (63%) and artificial surfaces (25%) within 2 miles, trees (64%) within 10 miles, and trees (75%) within 50 miles.

2 miles
98 ft
10 miles
305 ft
50 miles
1,079 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Florence 38 mi · Columbia 40 mi · West Columbia 42 mi · Saint Andrews 44 mi · Seven Oaks 47 mi · Lexington 52 mi · Summerville 63 mi · Goose Creek 67 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 Sumter (33.9204°, -80.3415°, elevation 171 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. 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).