This report describes the typical weather at the St. Augustine Airport (St. Augustine, Florida, United States) weather station over the course of an average year. It is based on the historical records from 1997 to 2012. Earlier records are either unavailable or unreliable.
St. Augustine, Florida has a warm humid temperate climate with hot summers and no dry season. The area within 25 mi of this station is covered by oceans and seas (46%), forests (39%), croplands (9%), and lakes and rivers (5%).
Over the course of a year, the temperature typically varies from 46°F to 89°F and is rarely below 33°F or above 93°F.
The warm season lasts from May 24 to September 24 with an average daily high temperature above 84°F. The hottest day of the year is July 21, with an average high of 89°F and low of 74°F.
The cold season lasts from December 4 to February 25 with an average daily high temperature below 69°F. The coldest day of the year is January 6, with an average low of 46°F and high of 64°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 10:13 hours of daylight; the longest day is June 20 with 14:04 hours of daylight.
The earliest sunrise is at 6:23am on June 12 and the latest sunset is at 8:31pm on June 29. The latest sunrise is at 7:41am on November 3 and the earliest sunset is at 5:25pm on December 3.
Daylight savings 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 5% (clear) to 26% (mostly clear). The sky is cloudiest on October 3 and clearest on April 21. The clearer part of the year begins around January 26. The cloudier part of the year begins around August 23.
On April 21, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 78% of the time, and overcast or mostly cloudy 20% of the time.
On October 3, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 41% of the time, and clear or mostly clear 54% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around July 27, occurring in 40% of days. Precipitation is least likely around November 29, occurring in 8% of days.
Over the entire year, the most common forms of precipitation are thunderstorms and light rain.
Thunderstorms are the most severe precipitation observed during 70% of those days with precipitation. They are most likely around July 27, when it is observed during 36% of all days.
Light rain is the most severe precipitation observed during 17% of those days with precipitation. It is most likely around February 15, when it is observed during 5% of all days.
During the warm season, which lasts from May 24 to September 24, there is a 34% 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 thunderstorms (85% of days with precipitation have at worst thunderstorms) and light rain (7%).
During the cold season, which lasts from December 4 to February 25, there is a 11% 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 light rain (40% of days with precipitation have at worst light rain), thunderstorms (32%), and moderate rain (22%).
Either snow is exceptionally unlikely to fall at any time during the year at this location or this station does not reliably report precipitation types.
The relative humidity typically ranges from 48% (comfortable) to 94% (very humid) over the course of the year, rarely dropping below 29% (dry) and reaching as high as 100% (very humid).
The air is driest around April 12, at which time the relative humidity drops below 59% (mildly humid) three days out of four; it is most humid around August 10, exceeding 92% (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 38°F (dry) to 77°F (oppressive) and is rarely below 21°F (dry) or above 79°F (oppressive).
There are two periods in the year that are most comfortable: The first is between January 1 and May 4 and the second is between October 23 and December 31. 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 16 mph (calm to moderate breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 9 mph (gentle breeze) occurs around May 20, at which time the average daily maximum wind speed is 16 mph (moderate breeze).
The lowest average wind speed of 7 mph (light breeze) occurs around July 28, at which time the average daily maximum wind speed is 14 mph (moderate breeze).