Charleston weather in May

In May, Charleston sees average daytime highs of 80°F and overnight lows near 66°F, with 2.7 in of rain across 9 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 77°F in the first days to 83°F by the end. The sky is clear or mostly clear about 41% of the time in May, and the air most often feels muggy.

Daylight stretches from about 13 h 18 min at the start of May to 14 hours by month's end. Set against the rest of the year, May is Charleston's 4th-clearest and 6th-windiest month. For the whole year in context, see Charleston's year-round climate.

Daytime high
80°
5th warmest
Overnight low
66°
8th coldest
Rainfall
2.7 in
9 wet days
Daylight
13 h 42 min
5:26 AM – 7:06 PM
Cloud cover
50%
4th clearest
Wind
8 mph
6th windiest
Solar energy
6.47 kWh/m²
Travel score
6.8
out of 10

Charleston is largest city in the U.S. state of South Carolina.

Density
470/km²
people per km²
Founded
1670

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 77°F in the first days to 83°F by the end.

A typical May day in Charleston reaches about 80°F in the afternoon and slips back to 66°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 74°F and 86°F. Set against its neighbours, May runs about 6°F warmer than April and about 5°F cooler than June.

50°60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
17762
27762
37763
47763
57863
67864
77864
87864
97864
107965
117965
127965
137965
147966
158066
168066
178067
188067
198067
208167
218168
228168
238168
248269
258269
268269
278269
288270
298370
308370
318371

How May really feels in Charleston

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.

Charleston 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 daysDaylight (hours)Travel score
Jan59° / 43°3.28.410.14.8
Feb62° / 45°3.37.810.85.4
Mar67° / 51°3.28.211.86.6
Apr73° / 58°2.97.512.87.4
May80° / 66°2.7913.76.8
Jun85° / 73°5.116.314.14.5
Jul88° / 76°5.417.813.93.7
Aug87° / 75°6.318.913.23.9
Sep83° / 71°5.113.312.25.5
Oct76° / 61°4.07.811.27.4
Nov67° / 51°2.66.810.36.9
Dec62° / 46°3.47.79.95.5

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 41% 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 39%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16337
26436
36436
46436
56436
66436
76436
86436
96436
106436
116436
126337
136337
146337
156337
166337
176238
186238
196139
206040
216040
226040
235941
245842
255842
265743
275743
285644
295545
305446
315446

Chance of precipitation in May

Any precipitation

Charleston gets around 2.7 in of rain over 9 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 30% and peaks near 43% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)
124
224
324
424
523
624
724
824
924
1025
1125
1226
1326
1427
1528
1628
1729
1830
1931
2031
2132
2233
2334
2434
2535
2636
2737
2838
2940
3041
3143

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the muggy band about 32% of days. Sticky, muggy-or-worse air turns up on roughly 53% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
12321282350
22220282460
32120282660
42019272760
51918272970
61818273070
71717273280
81617263380
91616263480
101516253590
1115152536100
1214142437110
1314142437120
1413132337130
1513122337140
1613122237160
1712122237170
1811122237190
1911112136210
2010112136220
219112035240
228112034270
237102034290
247101933310
25691932340
26591831370
27491730391
28481629421
29381628441
30271527471
31271427491

Wind in May

Winds average 8 mph in May.

Across May, daily wind ranges from about 8 mph on the calmest days to 9 mph at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (mph)Feels
19light breeze
29light breeze
39light breeze
49light breeze
59light breeze
69light breeze
79light breeze
89light breeze
98light breeze
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light breeze
168light breeze
178light breeze
188light breeze
198light breeze
208light breeze
218light breeze
228light breeze
238light breeze
248light breeze
258light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze
318light breeze

Sunrise & sunset in May

DaylightNight

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

Days grow by about 42 minutes over May. Sunrise moves from 5:39 AM to 5:18 AM, and sunset from 6:55 PM to 7:17 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.35:396:55
213.35:386:56
313.35:376:57
413.45:366:58
513.45:356:58
613.45:346:59
713.45:337:00
813.55:327:01
913.55:317:01
1013.55:307:02
1113.65:297:03
1213.65:297:03
1313.65:287:04
1413.65:277:05
1513.75:267:06
1613.75:267:06
1713.75:257:07
1813.75:247:08
1913.75:247:09
2013.85:237:09
2113.85:227:10
2213.85:227:11
2313.85:217:11
2413.95:217:12
2513.95:207:13
2613.95:207:13
2713.95:197:14
2813.95:197:15
2913.95:187:15
3014.05:187:16
3114.05:187:17

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 6.47 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 2.62 kWh/m² to a high of 6.47 kWh/m² in May across the year — May's 6.47 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
16.4Intense
26.4Intense
36.4Intense
46.4Intense
56.4Intense
66.4Intense
76.5Intense
86.5Intense
96.5Intense
106.5Intense
116.5Intense
126.5Intense
136.5Intense
146.5Intense
156.5Intense
166.5Intense
176.5Intense
186.5Intense
196.5Intense
206.5Intense
216.5Intense
226.5Intense
236.5Intense
246.4Intense
256.4Intense
266.4Intense
276.4Intense
286.4Intense
296.4Intense
306.3Intense
316.3Intense
Planning a trip in May

Hazard calendar for Charleston

In seasonPeak

None of Charleston's seasonal hazards are active in May. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Charleston 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 May a good time to visit Charleston?

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

6.8
Sightseeing
4th-best month of the year
6.7
Beach & pool
1st-best month of the year

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

What to pack for Charleston in May

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

In May, Charleston sees daytime highs around 80°F and nights near 66°F. Pack sun protection. Worth having: light clothes and rain gear. About 9 days see rain.

sun protectionlight clothesrain gear

Sea temperature near Charleston in May

The nearest coast averages about 73°F in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 11 mi away) is warmest in August at about 83°F and coldest in February near 60°F.

It's comfortable for a long swim from Apr 25 to Nov 19 — about 6.9 months when the water holds above 68°F.

60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan61Cool
Feb60Cool
Mar61Cool
Apr66Cool
May73Refreshing
Jun80Warm
Jul83Tropical
Aug83Tropical
Sep81Warm
Oct75Warm
Nov68Refreshing
Dec64Cool

UV index in Charleston 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 Charleston peaks around July 13 at about 10 (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 10Dec 19UV 3
UV index (midday)Level
Jan4Moderate
Feb5Moderate
Mar7High
Apr7Very high
May8Very high
Jun9Very high
Jul10Very high
Aug9Very high
Sep8Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Charleston 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 Charleston 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 Charleston?

Charleston sits at 32.8°N, 79.9°W, 20 ft above sea level, in United States. The nearest listed city is Mount Pleasant, 4.3 mi away.

Topography around Charleston

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

Within 2 miles, the terrain around Charleston has only modest variations in elevation — a maximum elevation change of 79 ft around an average of 7 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 131 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 226 ft.

The land around Charleston is covered by water (51%) and artificial surfaces (23%) within 2 miles, water (34%) and trees (33%) within 10 miles, and trees (51%) and water (37%) within 50 miles.

2 miles
79 ft
10 miles
131 ft
50 miles
226 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
May weather nearby: Mount Pleasant 4.3 mi · North Charleston 6.2 mi · Hanahan 11 mi · Goose Creek 16 mi · Summerville 22 mi · Hilton Head 62 mi · Hilton Head Island 62 mi · Bluffton 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 Charleston (32.7763°, -79.9327°, elevation 20 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).