This report describes the typical weather at the Yakima Air Terminal (McAllister Field) (Yakima, Washington, United States) 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.
Yakima, Washington has a cold semi-arid steppe climate. The area within 25 mi of this station is covered by shrublands (35%), grasslands (33%), croplands (25%), and forests (6%).
Over the course of a year, the temperature typically varies from 21°F to 89°F and is rarely below 8°F or above 98°F.
The warm season lasts from June 15 to September 12 with an average daily high temperature above 78°F. The hottest day of the year is July 30, with an average high of 89°F and low of 56°F.
The cold season lasts from November 19 to February 14 with an average daily high temperature below 45°F. The coldest day of the year is December 28, with an average low of 21°F and high of 34°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 8:35 hours of daylight; the longest day is June 20 with 15:51 hours of daylight.
The earliest sunrise is at 5:08am on June 17 and the latest sunset is at 9:00pm on June 24. The latest sunrise is at 7:48am on November 3 and the earliest sunset is at 4:14pm on December 10.
Daylight savings time (DST) is observed in this location during 2012, starting in the spring on March 11 and ending in the fall on November 4.
The median cloud cover ranges from 3% (clear) to 95% (overcast). The sky is cloudiest on January 4 and clearest on August 13. The clearer part of the year begins around March 29. The cloudier part of the year begins around November 2.
On August 13, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 85% of the time, and overcast or mostly cloudy 13% of the time.
On January 4, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 71% of the time, and clear or mostly clear 28% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around December 17, occurring in 51% of days. Precipitation is least likely around August 8, occurring in 14% of days.
Over the entire year, the most common forms of precipitation are light rain, light snow, and moderate rain.
Light rain is the most severe precipitation observed during 49% of those days with precipitation. It is most likely around April 9, when it is observed during 22% of all days.
Light snow is the most severe precipitation observed during 19% of those days with precipitation. It is most likely around December 25, when it is observed during 21% of all days.
Moderate rain is the most severe precipitation observed during 19% of those days with precipitation. It is most likely around November 26, when it is observed during 10% of all days.
During the warm season, which lasts from June 15 to September 12, there is a 17% 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 light rain (63% of days with precipitation have at worst light rain), thunderstorms (22%), and moderate rain (13%).
During the cold season, which lasts from November 19 to February 14, there is a 47% 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 light snow (37% of days with precipitation have at worst light snow), light rain (26%), moderate rain (20%), and moderate snow (13%).
The likelihood of snow falling is highest around December 25, occurring in 30% of days. The season in which it is relatively likely for snow to fall spans from November 9 to March 4.
Either snow rarely accumulates at this location or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 23% (dry) to 94% (very humid) over the course of the year, rarely dropping below 15% (dry) and reaching as high as 100% (very humid).
The air is driest around July 29, at which time the relative humidity drops below 27% (dry) three days out of four; it is most humid around December 5, exceeding 90% (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 18°F (dry) to 55°F (very comfortable) and is rarely below 3°F (dry) or above 62°F (mildy humid).
The time of the year between June 26 and September 13 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 16 mph (calm to moderate breeze), rarely exceeding 26 mph (strong breeze).
The highest average wind speed of 8 mph (gentle breeze) occurs around June 8, at which time the average daily maximum wind speed is 16 mph (moderate breeze).
The lowest average wind speed of 4 mph (light breeze) occurs around January 1, at which time the average daily maximum wind speed is 9 mph (gentle breeze).