This report describes the typical weather at the General Leobardo C. Ruiz International Airport (La Calera Airport) (Zacatecas, Mexico) weather station over the course of an average year. It is based on the historical records from 1990 to 2012. Earlier records are either unavailable or unreliable.
Zacatecas has a mild temperate climate with dry winters and warm summers. The area within 25 mi of this station is covered by grasslands (73%), shrublands (19%), and croplands (6%).
Over the course of a year, the temperature typically varies from 35°F to 83°F and is rarely below 26°F or above 89°F.
The warm season lasts from April 21 to June 20 with an average daily high temperature above 80°F. The hottest day of the year is May 29, with an average high of 83°F and low of 54°F.
The cold season lasts from December 4 to February 14 with an average daily high temperature below 70°F. The coldest day of the year is January 5, with an average low of 35°F and high of 68°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 10:44 hours of daylight; the longest day is June 20 with 13:33 hours of daylight.
The earliest sunrise is at 6:44am on March 31 and the latest sunset is at 8:41pm on July 5. The latest sunrise is at 7:54am on October 27 and the earliest sunset is at 6:04pm on November 25.
Daylight savings time (DST) is observed in this location during 2012, starting in the spring on April 1 and ending in the fall on October 28.
The median cloud cover ranges from 24% (mostly clear) to 77% (partly cloudy). The sky is cloudiest on July 21 and clearest on November 22. The clearer part of the year begins around October 14. The cloudier part of the year begins around May 14.
On November 22, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 67% of the time, and overcast or mostly cloudy 22% of the time.
On July 21, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 71% of the time, and clear or mostly clear 18% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around July 28, occurring in 29% of days. Precipitation is least likely around March 17, occurring in 3% of days.
Over the entire year, the most common forms of precipitation are moderate rain, drizzle, and light rain.
Moderate rain is the most severe precipitation observed during 51% of those days with precipitation. It is most likely around August 10, when it is observed during 16% of all days.
Drizzle is the most severe precipitation observed during 19% of those days with precipitation. It is most likely around September 9, when it is observed during 5% of all days.
Light rain is the most severe precipitation observed during 14% of those days with precipitation. It is most likely around July 9, when it is observed during 4% of all days.
During the warm season, which lasts from April 21 to June 20, there is a 14% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of moderate rain (50% of days with precipitation have at worst moderate rain), drizzle (19%), light rain (17%), and thunderstorms (9%).
During the cold season, which lasts from December 4 to February 14, there is a 7% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of moderate rain (45% of days with precipitation have at worst moderate rain), drizzle (28%), and light rain (17%).
Either snow is exceptionally unlikely to fall at any time during the year at this location or this station does not reliably report precipitation types.
The relative humidity typically ranges from 39% (comfortable) to 93% (very humid) over the course of the year, rarely dropping below 11% (very dry) and reaching as high as 100% (very humid).
The air is driest around March 17, at which time the relative humidity drops below 76% (humid) three days out of four; it is most humid around September 9, exceeding 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 year, the dew point typically varies from 16°F (dry) to 54°F (very comfortable) and is rarely below 3°F (dry) or above 59°F (comfortable).
The time of the year between June 23 and October 10 is the most comfortable, with dew points that are neither too dry nor too muggy.
Over the course of the year typical wind speeds vary from 0 mph to 23 mph (calm to fresh breeze), rarely exceeding 35 mph (high wind).
The highest average wind speed of 15 mph (moderate breeze) occurs around March 25, at which time the average daily maximum wind speed is 23 mph (fresh breeze).
The lowest average wind speed of 7 mph (light breeze) occurs around October 3, at which time the average daily maximum wind speed is 15 mph (moderate breeze).