This report describes the typical weather at the Charleston International Airport (Charleston Air Force Base) (Charleston, South Carolina, United States) weather station over the course of an average March. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
Charleston, South Carolina has a warm humid temperate climate with hot summers and no dry season. The area within 25 mi of this station is covered by forests (63%), oceans and seas (16%), croplands (12%), lakes and rivers (4%), and built-up areas (3%).
The month of March is characterized by rising daily high temperatures, with daily highs increasing from 66°F to 72°F over the course of the month, exceeding 82°F or dropping below 54°F only one day in ten.
Over the course of March, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 1:02 hours, implying an average day-over-day increase of 2.0 minutes.
The shortest day of the month is March 1 with 11:30 hours of daylight; the longest day is March 31 with 12:31 hours of daylight.
The earliest sunrise is at 6:36am on March 10; the latest sunset is at 7:40pm on March 31; the latest sunrise is at 7:35am on March 11; the earliest sunset is at 6:18pm on March 1.
Daylight savings time (DST) starts at 3:00am on March 11, 2012, shifting sunrise and sunset to an hour later.
The median cloud cover ranges from 39% (mostly clear) to 50% (partly cloudy). The trend is for the sky to be clearing with the median cloud cover decreasing by 10% from the start to the end of the month.
On March 30, the clearest day of the month, the sky is clear, mostly clear, or partly cloudy 64% of the time, and overcast or mostly cloudy 35% of the time.
On March 1, the cloudiest day of the month, the sky is overcast, mostly cloudy, or partly cloudy 52% of the time, and clear or mostly clear 47% of the time.
The average probability that some form of precipitation will be observed in a given day is 35%, with little variation over the course of the month.
Throughout March, the most common forms of precipitation are light rain, moderate rain, and thunderstorms.
Light rain is the most severe precipitation observed during 40% of those days with precipitation. It is most likely around March 2, when it is observed during 15% of all days.
Moderate rain is the most severe precipitation observed during 34% of those days with precipitation. It is most likely around March 1, when it is observed during 13% of all days.
Thunderstorms are the most severe precipitation observed during 17% of those days with precipitation. They are most likely around March 31, when it is observed during 8% of all days.
Either snow is exceptionally unlikely to fall at this location in March or this station does not reliably report precipitation types.
The relative humidity typically ranges from 41% (comfortable) to 91% (very humid) over the course of a typical March, rarely dropping below 22% (dry) and reaching as high as 100% (very humid).
The air is driest around March 5, at which time the relative humidity drops below 53% (mildly humid) three days out of four; it is most humid around March 22, rising above 86% (very humid) three days out of four.
Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.
Over the course of a typical March, the dew point typically varies from 35°F (dry) to 56°F (comfortable) and is rarely below 18°F (dry) or above 65°F (mildy humid).
The time of the month between March 2 and March 31 is the most comfortable, with dew points that are neither too dry nor too muggy.
Over the course of March typical wind speeds vary from 2 mph to 17 mph (light air to moderate breeze), rarely exceeding 23 mph (fresh breeze).
The highest average wind speed of 9 mph (gentle breeze) occurs around March 29, at which time the average daily maximum wind speed is 17 mph (moderate breeze).
The lowest average wind speed of 9 mph (gentle breeze) occurs around March 17, at which time the average daily maximum wind speed is 16 mph (moderate breeze).