This report describes the typical weather at the Key West International Airport (Key West, Florida, United States) weather station over the course of an average July. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
Key West, Florida has a tropical savanna climate with dry winters. The area within 25 mi of this station is covered by oceans and seas (98%).
The month of July is characterized by essentially constant daily high temperatures, with daily highs around 89°F throughout the month, exceeding 91°F or dropping below 86°F only one day in ten.
Over the course of July, the length of the day is essentially constant. The shortest day of the month is July 31 with 13:16 hours of daylight; the longest day is July 1 with 13:39 hours of daylight.
The earliest sunrise is at 6:42am on July 1; the latest sunset is at 8:20pm on July 1; the latest sunrise is at 6:55am on July 31; the earliest sunset is at 8:11pm on July 31.
Daylight savings time is observed in 2012 but it neither starts nor ends in July, so the entire month is in daylight time.
The median cloud cover is 46% (partly cloudy) and does not vary substantially over the course of the month.
On July 16, a representative day, the sky is clear or mostly clear 44% of the time, partly cloudy 29% of the time, and mostly cloudy or overcast 26% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around July 31, occurring in 60% of days. Precipitation is least likely around July 1, occurring in 54% of days.
Throughout July, the most common forms of precipitation are thunderstorms, light rain, and moderate rain.
Thunderstorms are the most severe precipitation observed during 71% of those days with precipitation. They are most likely around July 25, when it is observed during 44% of all days.
Light rain is the most severe precipitation observed during 13% of those days with precipitation. It is most likely around July 1, when it is observed during 9% of all days.
Moderate rain is the most severe precipitation observed during 11% of those days with precipitation. It is most likely around July 9, when it is observed during 7% of all days.
Either snow is exceptionally unlikely to fall at this location in July or this station does not reliably report precipitation types.
The relative humidity typically ranges from 63% (mildly humid) to 86% (very humid) over the course of a typical July, rarely dropping below 57% (mildly humid) and reaching as high as 99% (very humid).
The air is driest around July 22, at which time the relative humidity drops below 66% (mildly humid) three days out of four; it is most humid around July 3, rising above 81% (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 July, the dew point typically varies from 72°F (very muggy) to 77°F (oppressive) and is rarely below 69°F (muggy) or above 79°F (oppressive).
Over the course of July typical wind speeds vary from 4 mph to 14 mph (light breeze to moderate breeze), rarely exceeding 19 mph (fresh breeze).
The highest average wind speed of 9 mph (gentle breeze) occurs around July 1, at which time the average daily maximum wind speed is 14 mph (moderate breeze).
The lowest average wind speed of 9 mph (gentle breeze) occurs around July 20, at which time the average daily maximum wind speed is 13 mph (moderate breeze).