This report describes the typical weather at the Jackson Hole Airport (Jackson Hole, Wyoming, United States) weather station over the course of an average January. It is based on the historical records from 1980 to 2012. Earlier records are either unavailable or unreliable.
Jackson Hole, Wyoming has a humid subarctic continental climate with cool summers and no dry season. The area within 25 mi of this station is covered by forests (85%), croplands (9%), grasslands (4%), and lakes and rivers (2%).
The month of January is characterized by essentially constant daily high temperatures, with daily highs around 23°F throughout the month, exceeding 36°F or dropping below 9°F only one day in ten.
Over the course of January, the length of the day is gradually increasing. From the start to the end of the month, the length of the day increases by 51 minutes, implying an average day-over-day increase of 1.6 minutes.
The shortest day of the month is January 2 with 9:00 hours of daylight; the longest day is January 31 with 9:51 hours of daylight.
The earliest sunrise is at 7:41am on January 31; the latest sunset is at 5:32pm on January 31; the latest sunrise is at 7:57am on January 2; the earliest sunset is at 4:57pm on January 1.
Daylight savings time is observed in 2012 but it neither starts nor ends in January, so the entire month is in standard time.
The median cloud cover is 89% (mostly cloudy) and does not vary substantially over the course of the month.
On January 16, a representative day, the sky is clear or mostly clear 25% of the time, partly cloudy 3% of the time, and mostly cloudy or overcast 49% of the time.
The average probability that some form of precipitation will be observed in a given day is 32%, with little variation over the course of the month.
Throughout January, the most common forms of precipitation are light snow and moderate snow.
Light snow is the most severe precipitation observed during 80% of those days with precipitation. It is most likely around January 18, when it is observed during 27% of all days.
Moderate snow is the most severe precipitation observed during 17% of those days with precipitation. It is most likely around January 1, when it is observed during 6% of all days.
The likelihood of snow falling is highest around January 4, occurring in 33% of days.
Either snow rarely accumulates at this location in January or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 60% (mildly humid) to 92% (very humid) over the course of a typical January, rarely dropping below 43% (comfortable) and reaching as high as 100% (very humid).
The air is driest around January 31, at which time the relative humidity drops below 69% (mildly humid) three days out of four; it is most humid around January 11, rising above 88% (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 typical January, the dew point typically varies from -3°F (dry) to 18°F (dry) and is rarely below -24°F (dry) or above 30°F (dry).
Over the course of January typical wind speeds vary from 0 mph to 13 mph (calm to moderate breeze), rarely exceeding 24 mph (fresh breeze).
The highest average wind speed of 7 mph (light breeze) occurs around January 5, at which time the average daily maximum wind speed is 12 mph (moderate breeze).
The lowest average wind speed of 6 mph (light breeze) occurs around January 26, at which time the average daily maximum wind speed is 12 mph (gentle breeze).