This report describes the typical weather at the Lic. Gustavo Díaz Ordaz International Airport (Puerto Vallarta, Mexico) weather station over the course of an average December. It is based on the historical records from 1990 to 2012. Earlier records are either unavailable or unreliable.
Puerto Vallarta has a tropical savanna climate with dry winters. The area within 25 mi of this station is covered by forests (67%), oceans and seas (27%), and grasslands (6%).
The month of December is characterized by gradually falling daily high temperatures, with daily highs around 82°F throughout the month, exceeding 87°F or dropping below 77°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 27 with 10:53 hours of daylight; the longest day is December 1 with 10:58 hours of daylight.
The earliest sunrise is at 7:21am on December 1; the latest sunset is at 6:31pm on December 31; the latest sunrise is at 7:37am on December 31; the earliest sunset is at 6:19pm 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 ranges from 22% (mostly clear) to 29% (mostly clear). The trend is for the sky to be becoming cloudier with the median cloud cover increasing by 7% from the start to the end of the month.
On December 16, a representative day, the sky is clear or mostly clear 38% of the time, partly cloudy 12% of the time, and mostly cloudy or overcast 22% of the time.
The average probability that some form of precipitation will be observed in a given day is 6%, with little variation over the course of the month.
Throughout December, the most common forms of precipitation are light rain, moderate rain, drizzle, and thunderstorms.
Light rain is the most severe precipitation observed during 34% of those days with precipitation. It is most likely around December 30, when it is observed during 3% of all days.
Moderate rain is the most severe precipitation observed during 26% of those days with precipitation. It is most likely around December 1, when it is observed during 2% of all days.
Drizzle is the most severe precipitation observed during 22% of those days with precipitation. It is most likely around December 1, when it is observed during 2% of all days.
Thunderstorms are the most severe precipitation observed during 17% of those days with precipitation. They are most likely around December 1, when it is observed during 1% 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 55% (mildly humid) to 93% (very humid) over the course of a typical December, rarely dropping below 44% (comfortable) and reaching as high as 95% (very humid).
The air is driest around December 1, at which time the relative humidity drops below 60% (mildly humid) three days out of four; it is most humid around December 29, rising above 93% (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 58°F (comfortable) to 71°F (very muggy) and is rarely below 52°F (very comfortable) or above 75°F (very muggy).
Over the course of December typical wind speeds vary from 0 mph to 11 mph (calm to gentle breeze), rarely exceeding 16 mph (moderate breeze).
The highest average wind speed of 4 mph (light breeze) occurs around December 10, at which time the average daily maximum wind speed is 11 mph (gentle breeze).
The lowest average wind speed of 4 mph (light breeze) occurs around December 31, at which time the average daily maximum wind speed is 11 mph (gentle breeze).