Charleston weather in May: Charleston, South Carolina: normal highs, lows, rain and records for May
Charleston in May has a normal high of 84°F and a normal low of 63°F, a daily mean of 73°F, rising from 81°F on the 1st to 86°F by the 31st. Measurable precipitation falls on 8 days in a normal May, 3.32 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 29°C and low of 17°C, 84 mm of precipitation in May.
- NOAA stationCharleston International Airport
- Station IDUSW00013880
- Location32.90°N 80.04°W
- Elevation40 ft (12 m)
- From the center6 miles
- Population157,665
- Jan 60° 39°
- Feb 64° 42°
- Mar 70° 47°
- Apr 77° 55°
- May 84° 63°
- Jun 89° 70°
- Jul 91° 74°
- Aug 90° 73°
- Sep 85° 68°
- Oct 78° 58°
- Nov 69° 47°
- Dec 63° 42°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Charleston in May?
The normal high is 84°F and the normal low 63°F, for a daily mean of 73.3°F. May is 7.5°F warmer than April and 6.1°F cooler than June. May is the 5th warmest month of the year in Charleston and the 9th wettest. Across the month the normal high rises 5°F, from 81°F on May 1 to 86°F on May 31. From one year to the next May's mean temperature typically moves about 2.2°F either way (NOAA's standard deviation), so roughly two Mays in three average between 71°F and 76°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 33%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 81°F | 59°F | 25% | 17% |
| May 8 | 82°F | 61°F | 25% | 17% |
| May 15 | 84°F | 63°F | 27% | 18% |
| May 22 | 85°F | 65°F | 29% | 20% |
| May 31 | 86°F | 67°F | 33% | 22% |
Every day of May: normal high, low and chance of precipitation (warmest afternoon May 31, coldest night May 1)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| May 1 | 81°F | 59°F | 25% | 17% | 13 h 30 min |
| May 2 | 81°F | 59°F | 25% | 17% | 13 h 30 min |
| May 3 | 81°F | 59°F | 25% | 17% | 13 h 30 min |
| May 4 | 81°F | 60°F | 25% | 17% | 13 h 30 min |
| May 5 | 82°F | 60°F | 25% | 17% | 13 h 30 min |
| May 6 | 82°F | 60°F | 25% | 17% | 13 h 40 min |
| May 7 | 82°F | 60°F | 25% | 17% | 13 h 40 min |
| May 8 | 82°F | 61°F | 25% | 17% | 13 h 40 min |
| May 9 | 82°F | 61°F | 26% | 17% | 13 h 40 min |
| May 10 | 83°F | 61°F | 26% | 17% | 13 h 40 min |
| May 11 | 83°F | 62°F | 26% | 17% | 13 h 40 min |
| May 12 | 83°F | 62°F | 26% | 17% | 13 h 50 min |
| May 13 | 83°F | 62°F | 26% | 17% | 13 h 50 min |
| May 14 | 83°F | 63°F | 27% | 18% | 13 h 50 min |
| May 15 | 84°F | 63°F | 27% | 18% | 13 h 50 min |
| May 16 | 84°F | 63°F | 27% | 18% | 13 h 50 min |
| May 17 | 84°F | 63°F | 28% | 18% | 13 h 50 min |
| May 18 | 84°F | 64°F | 28% | 18% | 13 h 50 min |
| May 19 | 84°F | 64°F | 28% | 19% | 14 h |
| May 20 | 84°F | 64°F | 29% | 19% | 14 h |
| May 21 | 85°F | 64°F | 29% | 19% | 14 h |
| May 22 | 85°F | 65°F | 29% | 20% | 14 h |
| May 23 | 85°F | 65°F | 30% | 20% | 14 h |
| May 24 | 85°F | 65°F | 30% | 20% | 14 h |
| May 25 | 85°F | 66°F | 31% | 20% | 14 h |
| May 26 | 85°F | 66°F | 31% | 21% | 14 h |
| May 27 | 86°F | 66°F | 31% | 21% | 14 h |
| May 28 | 86°F | 66°F | 32% | 21% | 14 h 10 min |
| May 29 | 86°F | 67°F | 32% | 22% | 14 h 10 min |
| May 30 | 86°F | 67°F | 33% | 22% | 14 h 10 min |
| May 31 | 86°F | 67°F | 33% | 22% | 14 h 10 min |
- Normal high
- 84°FMay average
- Normal low
- 63°FMay average
- Precipitation
- 3.32 inmonth total
- Days with precipitation
- 80.01 inch or more
- Days at 90°F or more
- 5
- Daylight
- 13 h 30 min to 14 h 10 minMay 1 to May 31
- Days at 70°F or more
- 31
- Days at 80°F or more
- 24
- Sunshine
- 84%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00013880; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Charleston in May?
On a given May day the chance of 0.01 inch or more is 28% on average, highest around May 31 (33%). In all, 3.32 in falls on 8 days of a normal May, 1 of them with an inch or more.
In a normal May in Charleston, 5 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00013880.
How humid and windy is Charleston in May?
At 3 p.m. the normal temperature is 84°F with 55% relative humidity and a dew point of 66°F; at 6 a.m. it is 70°F with 90% humidity. The wind averages 8.0 mph, most often from the south in the afternoon. A dew point of 65°F or more feels muggy to most people.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 70°F | 67°F | 90% | 5.2 mph | 48% |
| 9 a.m. | 78°F | 67°F | 68% | 8.3 mph | 44% |
| noon | 83°F | 66°F | 56% | 9.5 mph | 29% |
| 3 p.m. | 84°F | 66°F | 55% | 11.5 mph | 31% |
| 6 p.m. | 80°F | 66°F | 63% | 11.0 mph | 47% |
| 9 p.m. | 74°F | 68°F | 80% | 7.4 mph | 61% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00013880. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for May in Charleston?
The warmest May temperature on Charleston's official record (since 1937) is 101°F, on May 29, 2019; the coldest is 36°F, on May 2, 1963. The wettest May brought 10.62 in (2018).
The May mean against the 1991-2020 normal of 73.3°F: 2021 71.7°F (−1.6), 2022 75.5°F (+2.2), 2023 71.4°F (−1.9), 2024 76.5°F (+3.3), 2025 75.7°F (+2.4), 2026 73.7°F (+0.4). 4 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 71.7°F | −1.6°F | 3.46 in |
| 2022 | 75.5°F | +2.2°F | 2.74 in |
| 2023 | 71.4°F | −1.9°F | 2.98 in |
| 2024 | 76.5°F | +3.3°F | 2.14 in |
| 2025 | 75.7°F | +2.4°F | 7.39 in |
| 2026 | 73.7°F | +0.4°F | 3.56 in |
Source: records: ACIS, NWS threaded record CHSthr; recent months: ACIS, station USW00013880. Records and recent months use complete months only.
How does May in Charleston compare across South Carolina?
Across the 73 places PlainClimate covers in South Carolina, May normal highs run from 70°F in Caesars Head to 86°F in Hampton; Charleston's is 84°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.