This report describes the typical weather at the Merced Municipal Airport (Merced, California, United States) weather station over the course of an average May. It is based on the historical records from 1998 to 2012. Earlier records are either unavailable or unreliable.
Merced, California has a cold semi-arid steppe climate. The area within 25 mi of this station is covered by grasslands (67%), croplands (26%), and forests (6%).
The month of May is characterized by rising daily high temperatures, with daily highs increasing from 77°F to 84°F over the course of the month, exceeding 95°F or dropping below 67°F only one day in ten.
Over the course of May, the length of the day is gradually increasing. From the start to the end of the month, the length of the day increases by 48 minutes, implying an average day-over-day increase of 1.5 minutes.
The shortest day of the month is May 1 with 13:45 hours of daylight; the longest day is May 31 with 14:33 hours of daylight.
The earliest sunrise is at 5:44am on May 30; the latest sunset is at 8:17pm on May 31; the latest sunrise is at 6:07am on May 1; the earliest sunset is at 7:52pm on May 1.
Daylight savings time is observed in 2012 but it neither starts nor ends in May, so the entire month is in daylight time.
The median cloud cover is 1% (clear) and does not vary substantially over the course of the month.
On May 16, a representative day, the sky is clear or mostly clear 84% of the time, partly cloudy 2% of the time, and mostly cloudy or overcast 10% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around May 1, occurring in 14% of days. Precipitation is least likely around May 29, occurring in 7% of days.
Throughout May, the most common forms of precipitation are light rain, moderate rain, and thunderstorms.
Light rain is the most severe precipitation observed during 58% of those days with precipitation. It is most likely around May 1, when it is observed during 8% of all days.
Moderate rain is the most severe precipitation observed during 22% of those days with precipitation. It is most likely around May 1, when it is observed during 3% of all days.
Thunderstorms are the most severe precipitation observed during 11% of those days with precipitation. They are most likely around May 4, when it is observed during 2% of all days.
Either snow is exceptionally unlikely to fall at this location in May or this station does not reliably report precipitation types.
The relative humidity typically ranges from 26% (dry) to 84% (humid) over the course of a typical May, rarely dropping below 16% (dry) and reaching as high as 98% (very humid).
The air is driest around May 19, at which time the relative humidity drops below 30% (comfortable) three days out of four; it is most humid around May 1, rising above 77% (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 May, the dew point typically varies from 38°F (dry) to 52°F (very comfortable) and is rarely below 28°F (dry) or above 59°F (comfortable).
Over the course of May typical wind speeds vary from 0 mph to 14 mph (calm to moderate breeze), rarely exceeding 19 mph (fresh breeze).
The highest average wind speed of 8 mph (gentle breeze) occurs around May 31, at which time the average daily maximum wind speed is 14 mph (moderate breeze).
The lowest average wind speed of 7 mph (light breeze) occurs around May 1, at which time the average daily maximum wind speed is 13 mph (moderate breeze).