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Charleston, South Carolina climate
Cfa Humid subtropical
Charleston has a seasonal warm-temperate climate (Humid subtropical, Köppen Cfa). The hottest month is July with an average daily high near 31°C, while the coldest is January averaging around 6°C at night. Around 1124 mm of precipitation falls each year, peaking in August (155 mm) and easing off in November (58 mm).
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresClear vs cloudy days
Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day countsCharleston climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 14 | 16 | 19 | 22 | 26 | 29 | 31 | 30 | 28 | 24 | 20 | 16 |
| Avg temp (°C) | 10 | 12 | 15 | 19 | 23 | 26 | 28 | 27 | 25 | 21 | 16 | 12 |
| Avg low (°C) | 6 | 8 | 11 | 15 | 20 | 23 | 25 | 25 | 23 | 17 | 12 | 8 |
| Precipitation (mm) | 65 | 65 | 77 | 75 | 66 | 123 | 129 | 155 | 133 | 103 | 58 | 74 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 14 | 16 | 19 | 22 | 26 | 29 |
| Avg temp (°C) | 10 | 12 | 15 | 19 | 23 | 26 |
| Avg low (°C) | 6 | 8 | 11 | 15 | 20 | 23 |
| Precipitation (mm) | 65 | 65 | 77 | 75 | 66 | 123 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 31 | 30 | 28 | 24 | 20 | 16 |
| Avg temp (°C) | 28 | 27 | 25 | 21 | 16 | 12 |
| Avg low (°C) | 25 | 25 | 23 | 17 | 12 | 8 |
| Precipitation (mm) | 129 | 155 | 133 | 103 | 58 | 74 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 8 | 8 | 8 | 7 | 7 | 10 | 12 | 12 | 9 | 7 | 6 | 8 |
| Days with high ≥ 32°C (days) | — | — | — | 0.2 | 1 | 5 | 9 | 7 | 2 | 0.2 | — | — |
| Days with low ≤ 0°C (days) | 3 | 1 | 0.2 | — | — | — | — | — | — | — | 0.1 | 1 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 8 | 8 | 8 | 7 | 7 | 10 |
| Days with high ≥ 32°C (days) | — | — | — | 0.2 | 1 | 5 |
| Days with low ≤ 0°C (days) | 3 | 1 | 0.2 | — | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 12 | 12 | 9 | 7 | 6 | 8 |
| Days with high ≥ 32°C (days) | 9 | 7 | 2 | 0.2 | — | — |
| Days with low ≤ 0°C (days) | — | — | — | — | 0.1 | 1 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 68 | 70 | 60 | 49 | 50 | 57 | 57 | 59 | 58 | 51 | 56 | 66 |
| Clear days (≤ 30% cloud) | 4 | 3 | 7 | 11 | 10 | 7 | 7 | 6 | 7 | 11 | 9 | 5 |
| Partly cloudy days (30–70%) | 11 | 9 | 11 | 10 | 11 | 12 | 13 | 12 | 10 | 8 | 9 | 10 |
| Cloudy days (≥ 70%) | 17 | 16 | 13 | 10 | 10 | 12 | 11 | 13 | 12 | 11 | 12 | 16 |
| Relative humidity (%) | 81 | 81 | 78 | 75 | 73 | 76 | 77 | 79 | 80 | 79 | 79 | 82 |
| Wind speed (m/s) | 1.5 | 1.5 | 1.5 | 1.4 | 1.3 | 1.2 | 1.2 | 1.2 | 1.3 | 1.3 | 1.4 | 1.4 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 68 | 70 | 60 | 49 | 50 | 57 |
| Clear days (≤ 30% cloud) | 4 | 3 | 7 | 11 | 10 | 7 |
| Partly cloudy days (30–70%) | 11 | 9 | 11 | 10 | 11 | 12 |
| Cloudy days (≥ 70%) | 17 | 16 | 13 | 10 | 10 | 12 |
| Relative humidity (%) | 81 | 81 | 78 | 75 | 73 | 76 |
| Wind speed (m/s) | 1.5 | 1.5 | 1.5 | 1.4 | 1.3 | 1.2 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 57 | 59 | 58 | 51 | 56 | 66 |
| Clear days (≤ 30% cloud) | 7 | 6 | 7 | 11 | 9 | 5 |
| Partly cloudy days (30–70%) | 13 | 12 | 10 | 8 | 9 | 10 |
| Cloudy days (≥ 70%) | 11 | 13 | 12 | 11 | 12 | 16 |
| Relative humidity (%) | 77 | 79 | 80 | 79 | 79 | 82 |
| Wind speed (m/s) | 1.2 | 1.2 | 1.3 | 1.3 | 1.4 | 1.4 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Dwtn Charleston (NOAA GHCN station USW00013782), inside the city.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.