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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 88°F, while the coldest is January averaging around 44°F at night. Around 44 inches of precipitation falls each year, peaking in August (6.1 inches) and easing off in November (2.3 inches).

☀️ Summers

Hot

Highs near 88°F in July.

About 24 days a year above 90 °F

❄️ Winters

Cool

Lows near 44°F in January.

About 6 freezing nights a year

🌧️ Rain

Wet

About 44 in of rain a year.

Wettest in August

⛅ Sky & trend

Partly cloudy

A roughly even mix of sun and cloud.

+0.5 °F vs 50 years ago

Temperature & precipitation

Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figures

Clear vs cloudy days

Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day counts

Charleston climate normals (1991–2020)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°F)	58	60	66	72	79	84	88	86	83	76	67	61
Avg temp (°F)	51	53	59	66	74	79	82	81	78	69	60	54
Avg low (°F)	44	46	52	60	68	74	77	77	73	63	53	47
Precipitation (in)	2.6	2.6	3.0	3.0	2.6	4.9	5.1	6.1	5.3	4.1	2.3	2.9

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Avg high (°F)	58	60	66	72	79	84
Avg temp (°F)	51	53	59	66	74	79
Avg low (°F)	44	46	52	60	68	74
Precipitation (in)	2.6	2.6	3.0	3.0	2.6	4.9

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°F)	88	86	83	76	67	61
Avg temp (°F)	82	81	78	69	60	54
Avg low (°F)	77	77	73	63	53	47
Precipitation (in)	5.1	6.1	5.3	4.1	2.3	2.9

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 ≥ 90°F (days)	—	—	—	0.2	1	5	9	7	2	0.2	—	—
Days with low ≤ 32°F (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 ≥ 90°F (days)	—	—	—	0.2	1	5
Days with low ≤ 32°F (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 ≥ 90°F (days)	9	7	2	0.2	—	—
Days with low ≤ 32°F (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 (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 (%)	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 (mph)	3.4	3.4	3.4	3.2	3.0	2.8

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 (mph)	2.7	2.6	2.9	3.0	3.0	3.1

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.

How we build these numbers →