This report describes the typical weather at the Los Angeles International Airport (Los Angeles, California, United States) weather station over the course of an average December. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
Los Angeles, California has a mediterranean climate with dry warm summers and mild winters. The area within 25 mi of this station is covered by oceans and seas (43%), built-up areas (40%), shrublands (11%), and forests (5%).
The month of December is characterized by gradually falling daily high temperatures, with daily highs around 66°F throughout the month, exceeding 76°F or dropping below 57°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 23 with 9:54 hours of daylight; the longest day is December 1 with 10:03 hours of daylight.
The earliest sunrise is at 6:41am on December 1; the latest sunset is at 4:55pm on December 31; the latest sunrise is at 6:59am on December 31; the earliest sunset is at 4:44pm on December 5.
Daylight savings 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 38% (mostly clear) to 46% (partly cloudy). The trend is for the sky to be becoming cloudier with the median cloud cover increasing by 8% from the start to the end of the month.
On December 16, a representative day, the sky is clear or mostly clear 49% of the time, partly cloudy 17% of the time, and mostly cloudy or overcast 34% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around December 31, occurring in 24% of days. Precipitation is least likely around December 1, occurring in 20% of days.
Throughout December, the most common forms of precipitation are moderate rain, light rain, and heavy rain.
Moderate rain is the most severe precipitation observed during 46% of those days with precipitation. It is most likely around December 26, when it is observed during 11% of all days.
Light rain is the most severe precipitation observed during 34% of those days with precipitation. It is most likely around December 31, when it is observed during 8% of all days.
Heavy rain is the most severe precipitation observed during 12% of those days with precipitation. It is most likely around December 31, when it is observed during 3% 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 38% (comfortable) to 84% (humid) over the course of a typical December, rarely dropping below 13% (very dry) and reaching as high as 100% (very humid).
The air is driest around December 6, at which time the relative humidity drops below 56% (mildly humid) three days out of four; it is most humid around December 11, rising above 76% (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 32°F (dry) to 51°F (very comfortable) and is rarely below 16°F (dry) or above 58°F (comfortable).
Over the course of December typical wind speeds vary from 0 mph to 12 mph (calm to gentle breeze), rarely exceeding 19 mph (fresh breeze).
The highest average wind speed of 6 mph (light breeze) occurs around December 3, at which time the average daily maximum wind speed is 12 mph (gentle breeze).
The lowest average wind speed of 6 mph (light breeze) occurs around December 24, at which time the average daily maximum wind speed is 12 mph (gentle breeze).