Average Weather On December 21 For Barrow, Alaska, USA

Location

This report describes the typical weather at the Wiley Post–Will Rogers Memorial Airport (Barrow, Alaska, United States) weather station over the course of an average December 21. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.

Barrow, Alaska has a polar tundra climate. The area within 25 mi of this station is covered by oceans and seas (70%), tundra (24%), and lakes and rivers (6%).

Temperature

The temperature typically varies from -10°F to -10°F and is rarely below -25°F or above 6°F.

Temperature

Average hourly temperature (black) with percentil bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

The coolest hours of the day are from 3pm to 9pm with the coldest at 6pm, at which time the temperature is below -3°F three days out of four.

The warmest hours of the day are from 3am to 5am with the hottest at 4am, at which time the temperature is above -18°F three days out of four.

The day has gained half its heat by midnight and lost it again by 8am.

Temperature Bands

The average fraction of time spent in various temperature bands: frigid (below 15°F), freezing (15°F to 32°F), cold (32°F to 50°F), cool (50°F to 65°F), comfortable (65°F to 75°F), warm (75°F to 85°F), hot (85°F to 100°F) and sweltering (above 100°F).

Sun

Solar noon is at 1:25pm.

Astronomical dawn and dusk are at 8:18am and 6:32pm, respectively.

Nautical dawn and dusk are at 9:46am and 5:05pm, respectively.

Civil dawn and dusk are at 11:55am and 2:55pm, respectively.

The Sun never rises above the horizon this time of year, always remaining at least below the horizon.

Solar Elevation

Elevation of the Sun above (positive) or below (negative) the horizon (black line). Yellow and gray fills indicate day and night, respectively. Light gray lines are the corresponding curves for the winter and summer equinoxes.

Clouds

The median cloud cover is 64% (partly cloudy) and does not vary substantially over the course of the day.

On average, the sky is clear or mostly clear 40% of the time, partly cloudy 15% of the time, and mostly cloudy or overcast 45% of the time.

Median Cloud Cover

Median hourly cloud coverage fraction (black line) with percentile bands (inner band from 40th to 60th percentile, outer band from 25th to 75th percentile).

Cloud Cover Types

The fraction of time spent in each of the five sky cover categories. From top (most blue) to bottom (most gray), the categories are clear, mostly clear, partly cloudy, mostly cloudy, and overcast. Pink indicates missing data. Outside the United States clear skies are often reported ambiguously, leading them to be lumped in with the missing data.

Precipitation

There is a 62% chance that precipitation will be observed at some point during the day.

The average measured liquid-equivalent quantity of precipitation is 0.002". Among only those days for which there is at least some measured precipitation, the average is 0.027" and the total rarely exceeds 0.037".

Probability of Precipitation

The fraction of days in which various types of precipitation are observed. If more than one type of precipitation is reported in a given day, the more severe precipitation is counted. For example, if light rain is observed in the same day as a thunderstorm, that day counts towards the thunderstorm totals. The order of severity is from the top down in this graph, with the most severe at the bottom.

When precipitation does occur it is most often in the form of slight snow (88% of days with precipitation have at worst slight snow) and moderate snow (10%).

Precipitation is observed with more or less equal probability throughout the day.

Types of Precipitation

Relative frequency of various types of precipitation over the course of a typical December 21.

Snow

There is a 97% chance that there will be snow on the ground. The average snow depth is 7.9". The snow depth is deeper than 9.5" one year in four and deeper than 12.8" one year in ten.

Humidity

The relative humidity typically ranges from 79% (humid) to 79% (humid), rarely dropping below 70% (mildly humid), or exceeding 91% (very humid).

The air is driest at 10am, at which time the relative humidity is less than 83% (humid) three days out of four; it is most humid at 5am, exceeding 74% (humid) three days out of four.

Relative Humidity

Average hourly humidity (black line) with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

Dew Point

The dew point ranges from -15°F to -15°F with an average of -15°F.

For reference, comfortable indoor conditions should have a relative humidity between 30% and 50% with a dew point of less than 65°F.

Dew Point

Average hourly dew point (black line) with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

Wind

The wind speed is 12 mph (gentle breeze) on average and is rarely outside the range 5 mph to 21 mph (light breeze to fresh breeze). The wind speed does not vary substantially during the course of the day.

Wind Speed

Average hourly wind speed (black line) with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

The wind is most often out of the east (31% of the time) and north east (22% of the time).

Wind Directions

The fraction of time spent with the wind blowing from the various directions over the entire day. Values do not sum to 100% because the wind direction is undefined when the wind speed is zero.

Wind Directions Over Day

The fraction of time spent with the wind blowing from the various directions on an hourly basis. Values do not sum to 100% because the wind direction is undefined when the wind speed is zero.