Charleston weather in May

May in Charleston: hot, rainy, with clean air — an excellent time to visit.

Updated September 2026 · climate normals from ERA5 reanalysis

Charleston🇺🇸 United States · US South · City80
  1. 74Jan
  2. 79Feb
  3. 86Mar
  4. 90Apr
  5. 80May
  6. 66Jun
  7. 58Jul
  8. 59Aug
  9. 69Sep
  10. 85Oct
  11. 86Nov
  12. 72Dec

#5 of 12 months in Charleston · #727 of 1413 destinations to visit in May · comfort 80/100 (tier A)

Days
26°C
Nights
21°C
Wet days
6
Sun
11.1 h
Humidity
75%
Daylight
14 h
Charleston, United States
Photo: John Hill · Pexels

Traveller notes on Charleston in May

Charleston-forum threads on early May weather call it largely comfortable, temperatures in the 70s and 80s Fahrenheit, though posters are honest that humidity can turn oppressive on some days even this early in the season. Mid-to-late May is where it noticeably tips over into genuinely warm and humid, ahead of the full summer swelter still to come. Downtown is also at its busiest in May, one of the year's three peak months alongside April and October, so crowds compound the heat rather than easing it. The record: 29.3C days feeling like a sticky 33C, 23.8C nights, 132mm across 8.4 days, a 25.7C sea, 80 percent humidity and 11.3 hours of sun - warmer and more humid than the largely-comfortable framing suggests by month's end.
RainbowRowMayRegular · May · 1 month ago · Read more on Tripadvisor ↗

Other months in Charleston

Regulars are specific this counts among the most unpredictable months of the year here, alongside January and early March, a trip landing anywhere from the upper 60s Fahrenheit down to the low 40s depending purely on which weather pattern happens to be passing through. Our row backs that mild, genuinely wet read, 17.5C over 10C nights feeling 7C, with 60mm of rain across 6 days and a real 20.4 kph wind. Regulars are consistent mostly sunshine remains the more common outcome despite the real cold-snap risk, a coat and scarf, maybe gloves, covering most of what's actually needed to stay comfortable. The sea sits at a cold 14.9C. The record: 7.7 hours of sun, humidity 77 percent and AQI 41.
MostUnpredictableSixtiesOrForties · February · 1 month ago · Read more on Tripadvisor ↗
Charleston-forum threads on July weather don't dress it up: temperatures regularly near 90F degrees on the thermometer, but the heat index pushes into triple digits most afternoons, and posters specifically flag downtown's brick and pavement as radiating extra heat back at pedestrians on top of the base forecast. Pop-up afternoon thunderstorms are described as a near-daily feature, arriving fast and hard enough that one side of a street can be pouring while the other stays completely dry - an umbrella is called essential rather than optional. Regulars are split on whether it's worth it: many say the heat and humidity are the only downside and everything indoors runs cold, while others recommend simply waiting for October instead. Early morning is the consistent window regulars suggest for outdoor sightseeing. The record: a scorching 31.3C by day feeling like a punishing 37C, 25.6C nights, 149mm across 11.4 days, 82 percent humidity, a 30.3C sea and 11.4 hours of sun.
KingStreetJulyRegular · July · 1 month ago · Read more on Tripadvisor ↗
November is the month Charleston regulars pick, and several call it their favourite: this is one of the two peak seasons here, spring being the other, because summer is the part locals escape. The weather they describe is good but genuinely unpredictable - it can be above 70F or it can be in the 40s and 50s, with highs around 70 typical and the nights dropping through the 60s into the 50s as the month runs. Our row's 19.9C day over a 12.5C night is the middle of that. Their packing answer is layers plus an umbrella, and their specific warning is not to plan on t-shirts alone, because the gap between early morning and mid-afternoon does the work. The record: 5.8 precipitation days carrying 49.2mm, humidity 75 percent and 7.9 hours of sun.
SeventyOrFiftyNoPromises · November · 1 month ago · Read more on Tripadvisor ↗
March in Charleston is the month regulars call variable before they call it good: some years it is in the upper 60s and low 70s F by the middle of the month, others it stays cold and wet throughout. What makes the gamble worth taking is the azaleas, which come out mid to late March and peak from the end of the month through the first two or three weeks of April - White Point Gardens and Hampton Park are the names they give. Two warnings travel with it. The garden festival pulls people from well outside the city, so downtown is busier than the tourist calendar suggests, and the tree pollen through March and early April gets described as sand-thick, the price of all the greenery. The record: 19.7C days, 12.7C nights, 5.7 precipitation days carrying 75.2mm, 9.1 hours of sun and a 21 kph wind.
PollenThickAsSand · March · 1 month ago · Read more on Tripadvisor ↗

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Charleston climate normals — May

Daytime high26°C / 80°F🥵 hot
Nighttime low21°C / 69°F
Feels like (high)29°C / 84°F
Sea temperature23°C / 73°F🙂 pleasant
Rainfall92 mm / 3.6 in🌧 rainy
Rainy days6 days
Humidity75%💦 very humid
Dew point19°C / 65°F
Sunshine11.1 h/day
Daylight13.9 h
Wind20 km/h / 12 mph
Air quality (US AQI)47🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Crowds in Charleston in May

How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.

BusySpoleto Festival USA(estimated)

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Peak crowdsBusyShoulder seasonQuiet

Best months for Charleston's weather

Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).

Fair weatherCharleston's best weather comes in March, April and November — separate windows, not one continuous season.

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Best weatherFair weatherToughest weather

What's on in Charleston in May

Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.

  • Festival

    Spoleto Festival USA

    22 May – 7 JunArts festivalCrowdedBook early

    Seventeen days of opera, theatre and chamber music in the historic churches and halls, with the free Piccolo Spoleto fringe running alongside it. Rooms in the peninsula are the year's dearest. Source ↗

What's on around the world in May →

Nearby, and something's on

Within 300 km of Charleston — a day trip or a short hop — with something on this month. Never part of the comfort score.

Where is Charleston?

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Charleston in May — FAQ

Is May a good time to visit Charleston?
May in Charleston: hot, rainy, with clean air — an excellent time to visit. It ranks #5 of 12 months for Charleston on SeasonMap's comfort score (80/100).
What is the weather like in Charleston in May?
In May, Charleston averages a daily high of 26.4°C and a low of 20.5°C, with about 91.6 mm of rain over roughly 5.8 rainy days.
What is the air quality in Charleston in May?
Charleston has a mean US Air Quality Index of about 47 in May.

Within 300 km: Hilton Head Island's Loggerhead nesting on 1 May – 31 Oct, and Myrtle Beach's Loggerhead nesting on 1 May – 31 Oct.