Sumter weather in May

In May, Sumter sees average daytime highs of 82°F and overnight lows near 63°F, with 3.1 in of rain across 9.5 wet days and about 13.7 hours of daylight. It is the 5th-warmest and 11th-wettest month of the year here.

Highs climb over the month, from about 79°F in the first days to 85°F by the end. The sky is clear or mostly clear about 35% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 18 min at the start of May to 14 h 06 min by month's end. Set against the rest of the year, May is Sumter's 7th-clearest and 7th-windiest month. For the whole year in context, see Sumter's year-round climate.

Daytime high
82°
5th warmest
Overnight low
63°
8th coldest
Rainfall
3.1 in
9.5 wet days
Daylight
13 h 48 min
5:25 AM – 7:10 PM
Cloud cover
55%
7th clearest
Wind
7 mph
7th windiest
Solar energy
6.17 kWh/m²
Travel score
6.2
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 May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 79°F in the first days to 85°F by the end.

A typical May day in Sumter reaches about 82°F in the afternoon and slips back to 63°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 73°F and 90°F. Set against its neighbours, May runs about 7°F warmer than April and about 6°F cooler than June.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
17958
27959
38059
48059
58060
68060
78060
88161
98161
108161
118162
128262
138262
148262
158263
168263
178263
188363
198364
208364
218364
228465
238465
248465
258465
268566
278566
288566
298567
308567
318567

How May really feels in Sumter

Once humidity and wind are folded in, May 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

May sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Sumter weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 11th-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 May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 20% of May, with mostly cloudy or overcast conditions the remaining 44%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15842
25842
35842
45842
55842
65941
75842
85842
95842
105842
115743
125743
135842
145743
155743
165743
175644
185644
195545
205545
215545
225446
235446
245446
255446
265347
275248
285248
295149
305050
315050

Chance of precipitation in May

Any precipitation

Sumter gets around 3.1 in of rain over 9.5 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 31% and peaks near 38% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)
128
228
328
428
528
627
727
827
927
1028
1128
1228
1328
1428
1529
1629
1730
1830
1931
2032
2133
2233
2334
2434
2535
2636
2736
2837
2937
3038
3138

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the dry band about 31% of days. Sticky, muggy-or-worse air turns up on roughly 26% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1512217100
2492218110
3482219110
4462120120
5452121130
6432122130
7422123140
8402124141
9392125151
10372126151
11362126161
12352127161
13332028172
14322028182
15312028192
16301928203
17291928213
18281928224
19271927234
20261827245
21251827256
22241727266
23221726277
24211726288
25201626299
261816263010
271715253111
281615253213
291414243314
301314243415
311213233417

Wind in May

Winds average 7 mph in May.

Across May, 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.

051015151015202531
Wind speed (mph)Feels
18light breeze
28light breeze
38light breeze
48light breeze
58light breeze
68light breeze
78light breeze
88light breeze
98light breeze
108light breeze
118light breeze
127light breeze
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 18 min at the start of May to 14 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 48 minutes over May. Sunrise moves from 5:38 AM to 5:17 AM, and sunset from 6:59 PM to 7:21 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.35:386:59
213.45:376:59
313.45:367:00
413.45:357:01
513.55:347:02
613.55:337:03
713.55:327:03
813.55:327:04
913.65:317:05
1013.65:307:06
1113.65:297:06
1213.75:287:07
1313.75:277:08
1413.75:267:09
1513.75:267:10
1613.85:257:10
1713.85:247:11
1813.85:237:12
1913.85:237:13
2013.95:227:13
2113.95:227:14
2213.95:217:15
2313.95:207:15
2413.95:207:16
2514.05:197:17
2614.05:197:18
2714.05:187:18
2814.05:187:19
2914.05:177:20
3014.15:177:20
3114.15:177:21

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 6.17 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 — May's 6.17 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
16.0Intense
26.1Intense
36.1Intense
46.1Intense
56.1Intense
66.1Intense
76.2Intense
86.2Intense
96.2Intense
106.2Intense
116.2Intense
126.2Intense
136.2Intense
146.2Intense
156.2Intense
166.2Intense
176.2Intense
186.2Intense
196.2Intense
206.2Intense
216.2Intense
226.2Intense
236.2Intense
246.2Intense
256.2Intense
266.2Intense
276.1Intense
286.1Intense
296.1Intense
306.1Intense
316.1Intense
Planning a trip in May

Is May a good time to visit Sumter?

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

6.2
Sightseeing
5th-best month of the year
6.9
Beach & pool
1st-best month of the year

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

What to pack for Sumter in May

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

In May, Sumter sees daytime highs around 82°F and nights near 63°F. Pack light clothes and sun protection. Worth having: rain gear. About 10 days see rain.

light clothessun protectionrain gear

UV index in Sumter in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May 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 May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May 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
May 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).