This report describes the typical weather at the Luis Muñoz Marín International Airport (San Juan, Puerto Rico) weather station over the course of an average June. It is based on the historical records from 1992 to 2012. Earlier records are either unavailable or unreliable.
San Juan has a tropical rainforest climate with no dry season. The area within 25 mi of this station is covered by oceans and seas (48%), forests (30%), grasslands (12%), marshes (6%), and croplands (3%).
The month of June is characterized by essentially constant daily high temperatures, with daily highs around 88°F throughout the month, exceeding 91°F or dropping below 85°F only one day in ten.
Over the course of June, the length of the day is essentially constant. The shortest day of the month is June 3 with 13:10 hours of daylight; the longest day is June 18 with 13:15 hours of daylight.
The earliest sunrise is at 5:47am on June 8; the latest sunset is at 7:04pm on June 30; the latest sunrise is at 5:51am on June 30; the earliest sunset is at 6:57pm on June 1.
Daylight savings time (DST) is not observed in 2012.
The median cloud cover is 39% (mostly clear) and does not vary substantially over the course of the month.
On June 15, a representative day, the sky is clear or mostly clear 48% of the time, partly cloudy 28% of the time, and mostly cloudy or overcast 20% of the time.
The average probability that some form of precipitation will be observed in a given day is 62%, with little variation over the course of the month.
Throughout June, the most common forms of precipitation are light rain, thunderstorms, heavy rain, and moderate rain.
Light rain is the most severe precipitation observed during 42% of those days with precipitation. It is most likely around June 5, when it is observed during 27% of all days.
Thunderstorms are the most severe precipitation observed during 30% of those days with precipitation. They are most likely around June 22, when it is observed during 20% of all days.
Heavy rain is the most severe precipitation observed during 14% of those days with precipitation. It is most likely around June 1, when it is observed during 9% of all days.
Moderate rain is the most severe precipitation observed during 14% of those days with precipitation. It is most likely around June 30, when it is observed during 9% of all days.
Either snow is exceptionally unlikely to fall at this location in June or this station does not reliably report precipitation types.
The relative humidity typically ranges from 62% (mildly humid) to 90% (very humid) over the course of a typical June, rarely dropping below 53% (mildly humid) and reaching as high as 97% (very humid).
The air is driest around June 4, at which time the relative humidity drops below 66% (mildly humid) three days out of four; it is most humid around June 1, rising above 87% (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 June, the dew point typically varies from 71°F (very muggy) to 76°F (oppressive) and is rarely below 69°F (muggy) or above 78°F (oppressive).
Over the course of June typical wind speeds vary from 0 mph to 19 mph (calm to fresh breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 10 mph (gentle breeze) occurs around June 30, at which time the average daily maximum wind speed is 19 mph (fresh breeze).
The lowest average wind speed of 8 mph (light breeze) occurs around June 1, at which time the average daily maximum wind speed is 17 mph (moderate breeze).