This report describes the typical weather at the Louisa County Airport (Louisa, Virginia, United States) weather station over the course of an average year. It is based on the historical records from 1999 to 2012. Earlier records are either unavailable or unreliable.
Louisa, Virginia 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 (98%).
Over the course of a year, the temperature typically varies from 28°F to 89°F and is rarely below 16°F or above 96°F.
The warm season lasts from May 29 to September 15 with an average daily high temperature above 81°F. The hottest day of the year is July 26, with an average high of 89°F and low of 69°F.
The cold season lasts from November 28 to February 28 with an average daily high temperature below 55°F. The coldest day of the year is January 26, with an average low of 28°F and high of 47°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 9:31 hours of daylight; the longest day is June 20 with 14:49 hours of daylight.
The earliest sunrise is at 5:48am on June 16 and the latest sunset is at 8:39pm on July 1. The latest sunrise is at 7:40am on November 3 and the earliest sunset is at 4:52pm on December 10.
Daylight saving time (DST) is observed in this location during 2012, starting in the spring on March 11 and ending in the fall on November 4.
The median cloud cover ranges from 18% (mostly clear) to 39% (mostly clear). The sky is cloudiest on September 12 and clearest on November 29. The clearer part of the year begins around October 10. The cloudier part of the year begins around March 23.
On November 29, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 65% of the time, and overcast or mostly cloudy 34% of the time.
On September 12, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 51% of the time, and clear or mostly clear 46% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around April 18, occurring in 26% of days. Precipitation is least likely around January 19, occurring in 15% of days.
Over the entire year, the most common forms of precipitation are moderate rain, heavy rain, and light rain.
Moderate rain is the most severe precipitation observed during 43% of those days with precipitation. It is most likely around April 23, when it is observed during 14% of all days.
Heavy rain is the most severe precipitation observed during 23% of those days with precipitation. It is most likely around June 13, when it is observed during 7% of all days.
Light rain is the most severe precipitation observed during 20% of those days with precipitation. It is most likely around August 4, when it is observed during 6% of all days.
During the warm season, which lasts from May 29 to September 15, there is a 21% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of moderate rain (39% of days with precipitation have at worst moderate rain), heavy rain (30%), and light rain (26%).
During the cold season, which lasts from November 28 to February 28, there is a 16% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of moderate rain (43% of days with precipitation have at worst moderate rain), moderate snow (15%), light snow (14%), and heavy rain (11%).
The likelihood of snow falling is highest around February 4, occurring in 7% of days.
Either snow rarely accumulates at this location or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 37% (comfortable) to 98% (very humid) over the course of the year, rarely dropping below 19% (dry) and reaching as high as 100% (very humid).
The air is driest around March 5, at which time the relative humidity drops below 44% (comfortable) three days out of four; it is most humid around September 28, exceeding 99% (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 year, the dew point typically varies from 18°F (dry) to 75°F (very muggy) and is rarely below 3°F (dry) or above 80°F (very oppressive).
There are two periods in the year that are most comfortable: The first is between April 13 and May 27 and the second is between September 25 and November 1. The air feels neither too dry nor too muggy during these periods.
Over the course of the year typical wind speeds vary from 0 mph to 12 mph (calm to moderate breeze), rarely exceeding 19 mph (fresh breeze).
The highest average wind speed of 6 mph (light breeze) occurs around April 8, at which time the average daily maximum wind speed is 12 mph (moderate breeze).
The lowest average wind speed of 3 mph (light air) occurs around August 10, at which time the average daily maximum wind speed is 8 mph (gentle breeze).