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Summerville, South Carolina climate
Cfa Humid subtropical
Summerville has a seasonal warm-temperate climate (Humid subtropical, Köppen Cfa). The hottest month is July with an average daily high near 91°F, while the coldest is January averaging around 39°F at night. Around 53 inches of precipitation falls each year, peaking in August (7.0 inches) and easing off in November (2.7 inches).
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 countsSummerville climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 60 | 64 | 70 | 77 | 84 | 89 | 91 | 90 | 85 | 78 | 69 | 63 |
| Avg temp (°F) | 50 | 53 | 59 | 66 | 73 | 79 | 83 | 81 | 77 | 68 | 58 | 52 |
| Avg low (°F) | 39 | 42 | 47 | 55 | 63 | 70 | 74 | 73 | 68 | 58 | 47 | 42 |
| Precipitation (in) | 3.4 | 3.1 | 3.4 | 3.3 | 3.3 | 6.2 | 6.6 | 7.0 | 6.0 | 4.3 | 2.7 | 3.4 |
| Snowfall (in) | 0.2 | 0.1 | — | — | — | — | — | — | — | — | — | — |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°F) | 60 | 64 | 70 | 77 | 84 | 89 |
| Avg temp (°F) | 50 | 53 | 59 | 66 | 73 | 79 |
| Avg low (°F) | 39 | 42 | 47 | 55 | 63 | 70 |
| Precipitation (in) | 3.4 | 3.1 | 3.4 | 3.3 | 3.3 | 6.2 |
| Snowfall (in) | 0.2 | 0.1 | — | — | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°F) | 91 | 90 | 85 | 78 | 69 | 63 |
| Avg temp (°F) | 83 | 81 | 77 | 68 | 58 | 52 |
| Avg low (°F) | 74 | 73 | 68 | 58 | 47 | 42 |
| Precipitation (in) | 6.6 | 7.0 | 6.0 | 4.3 | 2.7 | 3.4 |
| Snowfall (in) | — | — | — | — | — | — |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 9 | 8 | 8 | 8 | 8 | 12 | 13 | 13 | 10 | 7 | 7 | 9 |
| Days with high ≥ 90°F (days) | — | — | 0.0 | 0.6 | 5 | 14 | 21 | 17 | 6 | 0.5 | — | — |
| Days with low ≤ 32°F (days) | 9 | 4 | 2 | 0.0 | — | — | — | — | — | — | 1 | 6 |
| Days with snowfall ≥ 1 in (days) | 0.1 | 0.0 | — | — | — | — | — | — | — | — | — | — |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 9 | 8 | 8 | 8 | 8 | 12 |
| Days with high ≥ 90°F (days) | — | — | 0.0 | 0.6 | 5 | 14 |
| Days with low ≤ 32°F (days) | 9 | 4 | 2 | 0.0 | — | — |
| Days with snowfall ≥ 1 in (days) | 0.1 | 0.0 | — | — | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 13 | 13 | 10 | 7 | 7 | 9 |
| Days with high ≥ 90°F (days) | 21 | 17 | 6 | 0.5 | — | — |
| Days with low ≤ 32°F (days) | — | — | — | — | 1 | 6 |
| Days with snowfall ≥ 1 in (days) | — | — | — | — | — | — |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 59 | 60 | 54 | 49 | 50 | 55 | 54 | 58 | 55 | 46 | 50 | 58 |
| Clear days (≤ 30% cloud) | 8 | 6 | 9 | 10 | 10 | 7 | 7 | 6 | 8 | 13 | 11 | 8 |
| Partly cloudy days (30–70%) | 10 | 10 | 10 | 11 | 12 | 12 | 14 | 13 | 11 | 8 | 9 | 9 |
| Cloudy days (≥ 70%) | 13 | 12 | 12 | 9 | 10 | 11 | 10 | 12 | 11 | 10 | 10 | 13 |
| Relative humidity (%) | 81 | 81 | 78 | 75 | 73 | 76 | 77 | 79 | 80 | 79 | 79 | 82 |
| Wind speed (mph) | 3.4 | 3.4 | 3.4 | 3.2 | 3.0 | 2.8 | 2.7 | 2.6 | 2.9 | 3.0 | 3.0 | 3.1 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 59 | 60 | 54 | 49 | 50 | 55 |
| Clear days (≤ 30% cloud) | 8 | 6 | 9 | 10 | 10 | 7 |
| Partly cloudy days (30–70%) | 10 | 10 | 10 | 11 | 12 | 12 |
| Cloudy days (≥ 70%) | 13 | 12 | 12 | 9 | 10 | 11 |
| Relative humidity (%) | 81 | 81 | 78 | 75 | 73 | 76 |
| Wind speed (mph) | 3.4 | 3.4 | 3.4 | 3.2 | 3.0 | 2.8 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 54 | 58 | 55 | 46 | 50 | 58 |
| Clear days (≤ 30% cloud) | 7 | 6 | 8 | 13 | 11 | 8 |
| Partly cloudy days (30–70%) | 14 | 13 | 11 | 8 | 9 | 9 |
| Cloudy days (≥ 70%) | 10 | 12 | 11 | 10 | 10 | 13 |
| Relative humidity (%) | 77 | 79 | 80 | 79 | 79 | 82 |
| Wind speed (mph) | 2.7 | 2.6 | 2.9 | 3.0 | 3.0 | 3.1 |
30-year delta table (1991–2020 minus 1981–2010, °F)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Δ Max temp | +1.2 | +1.0 | +0.5 | +0.7 | +0.4 | +0.1 | +0.2 | +0.3 | +0.6 | +0.8 | -0.4 | +1.1 |
| Δ Avg temp | +1.2 | +1.0 | +0.6 | +1.0 | +0.8 | +0.4 | +0.4 | +0.5 | +0.9 | +0.9 | -0.3 | +1.4 |
| Δ Min temp | +1.4 | +1.0 | +0.6 | +1.2 | +1.2 | +0.8 | +0.7 | +0.8 | +1.1 | +0.9 | -0.4 | +1.5 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Δ Max temp | +1.2 | +1.0 | +0.5 | +0.7 | +0.4 | +0.1 |
| Δ Avg temp | +1.2 | +1.0 | +0.6 | +1.0 | +0.8 | +0.4 |
| Δ Min temp | +1.4 | +1.0 | +0.6 | +1.2 | +1.2 | +0.8 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Δ Max temp | +0.2 | +0.3 | +0.6 | +0.8 | -0.4 | +1.1 |
| Δ Avg temp | +0.4 | +0.5 | +0.9 | +0.9 | -0.3 | +1.4 |
| Δ Min temp | +0.7 | +0.8 | +1.1 | +0.9 | -0.4 | +1.5 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Charleston Intl AP (NOAA GHCN station USW00013880), about 18 km from the city centre.
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.