This report describes the typical weather at the Cozumel International Airport (Cozumel, Mexico) weather station over the course of an average December. It is based on the historical records from 1991 to 2012. Earlier records are either unavailable or unreliable.
Cozumel has a tropical monsoon climate with short dry season. The area within 25 mi of this station is covered by oceans and seas (69%) and forests (30%).
The month of December is characterized by gradually falling daily high temperatures, with daily highs around 82°F throughout the month, exceeding 86°F or dropping below 76°F only one day in ten.
Over the course of December, the length of the day is essentially constant. The shortest day of the month is December 20 with 10:53 hours of daylight; the longest day is December 2 with 10:58 hours of daylight.
The earliest sunrise is at 6:08am on December 1; the latest sunset is at 5:19pm on December 31; the latest sunrise is at 6:24am on December 30; the earliest sunset is at 5:06pm on December 1.
Daylight saving time is observed in 2012 but it neither starts nor ends in December, so the entire month is in standard time.
The median cloud cover is 53% (partly cloudy) and does not vary substantially over the course of the month.
On December 16, a representative day, the sky is clear or mostly clear 11% of the time, partly cloudy 21% of the time, and mostly cloudy or overcast 19% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around December 1, occurring in 24% of days. Precipitation is least likely around December 31, occurring in 20% of days.
Throughout December, the most common forms of precipitation are light rain and moderate rain.
Light rain is the most severe precipitation observed during 50% of those days with precipitation. It is most likely around December 15, when it is observed during 12% of all days.
Moderate rain is the most severe precipitation observed during 34% of those days with precipitation. It is most likely around December 1, when it is observed during 9% of all days.
Either snow is exceptionally unlikely to fall at this location in December or this station does not reliably report precipitation types.
The relative humidity typically ranges from 64% (mildly humid) to 93% (very humid) over the course of a typical December, rarely dropping below 55% (mildly humid) and reaching as high as 100% (very humid).
The air is driest around December 28, at which time the relative humidity drops below 69% (mildly humid) three days out of four; it is most humid around December 14, rising above 88% (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 December, the dew point typically varies from 65°F (mildy humid) to 73°F (very muggy) and is rarely below 58°F (comfortable) or above 77°F (oppressive).
Over the course of December typical wind speeds vary from 0 mph to 15 mph (calm to moderate breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 8 mph (gentle breeze) occurs around December 29, at which time the average daily maximum wind speed is 15 mph (moderate breeze).
The lowest average wind speed of 7 mph (light breeze) occurs around December 1, at which time the average daily maximum wind speed is 14 mph (moderate breeze).