This report describes the typical weather at the Comodoro Arturo Merino Benítez International Airport (Santiago, Chile) weather station over the course of an average January. It is based on the historical records from 1975 to 2012. Earlier records are either unavailable or unreliable.
Santiago has a mediterranean climate with dry warm summers and mild winters. The area within 25 mi of this station is covered by grasslands (44%), shrublands (25%), croplands (22%), and built-up areas (6%).
The month of January is characterized by essentially constant daily high temperatures, with daily highs around 85°F throughout the month, exceeding 90°F or dropping below 79°F only one day in ten.
Over the course of January, the length of the day is gradually decreasing. The shortest day of the month is January 31 with 13:44 hours of daylight; the longest day is January 1 with 14:19 hours of daylight.
The earliest sunrise is at 6:37am on January 1; the latest sunset is at 8:57pm on January 4; the latest sunrise is at 7:05am on January 31; the earliest sunset is at 8:49pm on January 30.
Daylight saving time is observed in 2012 but it neither starts nor ends in January, so the entire month is in daylight time.
The median cloud cover is 2% (clear) and does not vary substantially over the course of the month.
On January 16, a representative day, the sky is clear or mostly clear 64% of the time, partly cloudy 7% of the time, and mostly cloudy or overcast 5% of the time.
The average probability that some form of precipitation will be observed in a given day is 3%, with little variation over the course of the month.
Throughout January, the most common forms of precipitation are drizzle, moderate rain, thunderstorms, and light rain.
Drizzle is the most severe precipitation observed during 34% of those days with precipitation. It is most likely around January 3, when it is observed during 1% of all days.
Moderate rain is the most severe precipitation observed during 25% of those days with precipitation. It is most likely around January 27, when it is observed during 1% of all days.
Thunderstorms are the most severe precipitation observed during 19% of those days with precipitation. They are most likely around January 22, when it is observed during 1% of all days.
Light rain is the most severe precipitation observed during 15% of those days with precipitation. It is most likely around January 2, when it is observed during 1% of all days.
Either snow is exceptionally unlikely to fall at this location in January or this station does not reliably report precipitation types.
The relative humidity typically ranges from 31% (comfortable) to 85% (very humid) over the course of a typical January, rarely dropping below 21% (dry) and reaching as high as 100% (very humid).
The air is driest around January 7, at which time the relative humidity drops below 36% (comfortable) three days out of four; it is most humid around January 28, rising above 78% (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 January, the dew point typically varies from 45°F (dry) to 55°F (very comfortable) and is rarely below 38°F (dry) or above 60°F (comfortable).
The time of the month between January 1 and January 31 is the most comfortable, with dew points that are neither too dry nor too muggy.
Over the course of January typical wind speeds vary from 0 mph to 18 mph (calm to fresh breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 8 mph (gentle breeze) occurs around January 2, at which time the average daily maximum wind speed is 18 mph (fresh breeze).
The lowest average wind speed of 7 mph (light breeze) occurs around January 31, at which time the average daily maximum wind speed is 17 mph (moderate breeze).