| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 14.8° | 6.6° | 56.2mm | 8.2 | 67 |
| February | 16.1° | 8.1° | 68mm | 8.2 | 71 |
| March | 19.1° | 11.5° | 78.5mm | 8.1 | 81 |
| April | 22.7° | 15.6° | 76.2mm | 6.6 | 87 |
| May | 26.3° | 20.1° | 69.1mm | 6.8 | 86 |
| June | 29.4° | 23.7° | 122.6mm | 10.4 | 70 |
| July | 31° | 25.2° | 133.3mm | 11.9 | 60 |
| August | 30.5° | 25° | 156.5mm | 11.9 | 62 |
| September | 28.4° | 22.6° | 128.9mm | 8.7 | 77 |
| October | 24.5° | 17.6° | 90.3mm | 6.4 | 87 |
| November | 19.7° | 11.9° | 54.2mm | 6.4 | 86 |
| December | 16.4° | 8.5° | 76.2mm | 8.4 | 72 |
January in Charleston averages a daily high of 14.8°C with nights around 6.6°C. Expect roughly 8.2 wet days totalling 56.2mm. Generally workable, with some weather to plan around.
February in Charleston averages a daily high of 16.1°C with nights around 8.1°C. Expect roughly 8.2 wet days totalling 68mm. Generally workable, with some weather to plan around.
March in Charleston averages a daily high of 19.1°C with nights around 11.5°C. Expect roughly 8.1 wet days totalling 78.5mm. Comfortable conditions for being outdoors all day.
April in Charleston averages a daily high of 22.7°C with nights around 15.6°C. Expect roughly 6.6 wet days totalling 76.2mm. Comfortable conditions for being outdoors all day.
May in Charleston averages a daily high of 26.3°C with nights around 20.1°C. Expect roughly 6.8 wet days totalling 69.1mm. Comfortable conditions for being outdoors all day.
June in Charleston averages a daily high of 29.4°C with nights around 23.7°C. Expect roughly 10.4 wet days totalling 122.6mm. Generally workable, with some weather to plan around.
July in Charleston averages a daily high of 31°C with nights around 25.2°C. Expect roughly 11.9 wet days totalling 133.3mm. Generally workable, with some weather to plan around.
August in Charleston averages a daily high of 30.5°C with nights around 25°C. Expect roughly 11.9 wet days totalling 156.5mm. Generally workable, with some weather to plan around.
September in Charleston averages a daily high of 28.4°C with nights around 22.6°C. Expect roughly 8.7 wet days totalling 128.9mm. Comfortable conditions for being outdoors all day.
October in Charleston averages a daily high of 24.5°C with nights around 17.6°C. Expect roughly 6.4 wet days totalling 90.3mm. Comfortable conditions for being outdoors all day.
November in Charleston averages a daily high of 19.7°C with nights around 11.9°C. Expect roughly 6.4 wet days totalling 54.2mm. Comfortable conditions for being outdoors all day.
December in Charleston averages a daily high of 16.4°C with nights around 8.5°C. Expect roughly 8.4 wet days totalling 76.2mm. Generally workable, with some weather to plan around.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Charleston peaks at 87.
Based on 30 years of records, March–May scores highest for comfort in Charleston, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 31°C.
August is the wettest, averaging 156.5mm of rain across roughly 11.9 wet days.
January is the coolest month, with average daily highs around 14.8°C.