This report describes the typical weather at the Manuel Crescencio Rejón International Airport (Mérida, Mexico) weather station over the course of an average year. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
Mérida has a hot semi-arid steppe climate. The area within 25 mi of this station is covered by forests (81%), croplands (9%), grasslands (5%), and marshes (3%).
Over the course of a year, the temperature typically varies from 64°F to 98°F and is rarely below 56°F or above 103°F.
The warm season lasts from April 15 to June 9 with an average daily high temperature above 95°F. The hottest day of the year is May 7, with an average high of 98°F and low of 73°F.
The cold season lasts from November 9 to February 14 with an average daily high temperature below 87°F. The coldest day of the year is January 19, with an average low of 64°F and high of 85°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 10:51 hours of daylight; the longest day is June 20 with 13:25 hours of daylight.
The earliest sunrise is at 5:52am on March 31 and the latest sunset is at 7:44pm on July 6. The latest sunrise is at 6:59am on October 27 and the earliest sunset is at 5:16pm on November 23.
Daylight saving 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 46% (partly cloudy) to 76% (partly cloudy). The sky is cloudiest on September 7 and clearest on March 10. The clearer part of the year begins around November 8. The cloudier part of the year begins around May 21.
On March 10, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 58% of the time, and overcast or mostly cloudy 38% of the time.
On September 7, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 75% of the time, and clear or mostly clear 20% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around August 18, occurring in 59% of days. Precipitation is least likely around April 4, occurring in 12% of days.
Over the entire year, the most common forms of precipitation are thunderstorms, moderate rain, and light rain.
Thunderstorms are the most severe precipitation observed during 50% of those days with precipitation. They are most likely around August 18, when it is observed during 44% of all days.
Moderate rain is the most severe precipitation observed during 23% of those days with precipitation. It is most likely around October 5, when it is observed during 11% of all days.
Light rain is the most severe precipitation observed during 17% of those days with precipitation. It is most likely around October 11, when it is observed during 7% of all days.
During the warm season, which lasts from April 15 to June 9, there is a 24% 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 thunderstorms (48% of days with precipitation have at worst thunderstorms), moderate rain (24%), light rain (17%), and drizzle (9%).
During the cold season, which lasts from November 9 to February 14, there is a 20% 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 (34% of days with precipitation have at worst moderate rain), light rain (30%), drizzle (20%), and thunderstorms (15%).
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 33% (comfortable) to 99% (very humid) over the course of the year, rarely dropping below 23% (dry) and reaching as high as 100% (very humid).
The air is driest around April 29, at which time the relative humidity drops below 38% (comfortable) three days out of four; it is most humid around September 9, exceeding 99% (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 57°F (comfortable) to 78°F (oppressive) and is rarely below 49°F (dry) or above 82°F (very oppressive).
Over the course of the year typical wind speeds vary from 0 mph to 21 mph (calm to fresh breeze), rarely exceeding 30 mph (strong breeze).
The highest average wind speed of 12 mph (gentle breeze) occurs around May 2, at which time the average daily maximum wind speed is 20 mph (fresh breeze).
The lowest average wind speed of 6 mph (light breeze) occurs around September 25, at which time the average daily maximum wind speed is 14 mph (moderate breeze).