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Average Weather in Deltana Alaska, United States

In Deltana, the summers are cool and mostly cloudy and the winters are long, frigid, snowy, and partly cloudy. Over the course of the year, the temperature typically varies from -6°F to 68°F and is rarely below -33°F or above 77°F.

The warm season lasts for 3.6 months, from May 18 to September 7, with an average daily high temperature above 56°F. The hottest day of the year is July 7, with an average high of 68°F and low of 52°F.

The cold season lasts for 4.1 months, from November 2 to March 4, with an average daily high temperature below 20°F. The coldest day of the year is January 16, with an average low of -6°F and high of 8°F.

Average High and Low Temperature

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature

Average Hourly Temperature in DeltanaJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMcoldcoolfrigidchillyfreezingcomfortable
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < chilly < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Clouds

In Deltana, the average percentage of the sky covered by clouds experiences mild seasonal variation over the course of the year.

The clearer part of the year in Deltana begins around December 31 and lasts for 3.1 months, ending around April 2. On March 9, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 47% of the time, and overcast or mostly cloudy 53% of the time.

The cloudier part of the year begins around April 2 and lasts for 8.9 months, ending around December 31. On September 27, the cloudiest day of the year, the sky is overcast or mostly cloudy 66% of the time, and clear, mostly clear, or partly cloudy 34% of the time.

Cloud Cover Categories

Cloud Cover Categories in DeltanaclearercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Mar 947%Mar 947%Sep 2734%Sep 2734%Dec 3140%Dec 3140%clearpartly cloudymostly cloudyovercastmostly clear
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Deltana varies significantly throughout the year.

The wetter season lasts 4.3 months, from May 23 to October 2, with a greater than 25% chance of a given day being a wet day. The chance of a wet day peaks at 45% on July 3.

The drier season lasts 7.7 months, from October 2 to May 23. The smallest chance of a wet day is 5% on March 18.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in Deltana changes throughout the year.

Rain alone is the most common for 6.0 months, from April 14 to October 15. The highest chance of a day with rain alone is 45% on July 3.

Snow alone is the most common for 5.9 months, from October 15 to April 14. The highest chance of a day with snow alone is 11% on December 17.

Daily Chance of Precipitation

Daily Chance of Precipitation in DeltanasnowrainsnowJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Jul 345%Jul 345%Mar 185%Mar 185%Oct 1518%Oct 1518%Jan 111%Jan 111%May 2326%May 2326%rainsnowmixed
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Deltana experiences extreme seasonal variation in monthly rainfall.

The rainy period of the year lasts for 5.7 months, from April 25 to October 16, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around July 2, with an average total accumulation of 4.1 inches.

The rainless period of the year lasts for 6.3 months, from October 16 to April 25. The least rain falls around December 27, with an average total accumulation of 0.0 inches.

Average Monthly Rainfall

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Snowfall

We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Deltana experiences some seasonal variation in monthly liquid-equivalent snowfall.

The snowy period of the year lasts for 7.9 months, from September 13 to May 10, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around October 29, with an average total liquid-equivalent accumulation of 0.5 inches.

The snowless period of the year lasts for 4.1 months, from May 10 to September 13. The least snow falls around July 11, with an average total liquid-equivalent accumulation of 0.0 inches.

Average Liquid-Equivalent Monthly Snowfall

The average liquid-equivalent snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.

Sun

The length of the day in Deltana varies extremely over the course of the year. In 2017, the shortest day is December 21, with 4 hours, 16 minutes of daylight; the longest day is June 20, with 20 hours, 55 minutes of daylight.

Hours of Daylight and Twilight

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 3:14 AM on June 19, and the latest sunrise is 7 hours, 17 minutes later at 10:31 AM on December 24. The earliest sunset is at 2:46 PM on December 17, and the latest sunset is 9 hours, 24 minutes later at 12:10 AM on June 21.

Daylight saving time (DST) is observed in Deltana during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.

Sunrise & Sunset with Twilight and Daylight Saving Time

Sunrise & Sunset with Twilight and Daylight Saving Time in DeltanaJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 193:14 AMJun 193:14 AM12:10 AMJun 2112:10 AMJun 21Dec 172:46 PMDec 172:46 PM10:31 AMDec 2410:31 AMDec 24Mar 12DSTMar 12DSTDSTNov 5DSTNov 5daynightnightnightnight
The solar day over the course of the year 2017. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

Humidity

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The perceived humidity level in Deltana, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.

Humidity Comfort Levels

Humidity Comfort Levels in DeltanaJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Jul 30%Jul 30%drydry
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Deltana experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 4.1 months, from November 16 to March 20, with average wind speeds of more than 3.1 miles per hour. The windiest day of the year is January 8, with an average hourly wind speed of 3.7 miles per hour.

The calmer time of year lasts for 7.9 months, from March 20 to November 16. The calmest day of the year is July 14, with an average hourly wind speed of 2.6 miles per hour.

Average Wind Speed

Average Wind Speed in DeltanawindywindyJanFebMarAprMayJunJulAugSepOctNovDec0.0 mph0.5 mph1.0 mph1.5 mph2.0 mph2.5 mph3.0 mph3.5 mph4.0 mph4.5 mph5.0 mph5.5 mph6.0 mphJan 83.7 mphJan 83.7 mphJul 142.6 mphJul 142.6 mphNov 163.1 mphNov 163.1 mphMar 203.1 mphMar 203.1 mph
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in Deltana varies throughout the year.

The wind is most often from the west for 1.8 months, from June 6 to July 30, with a peak percentage of 43% on July 18. The wind is most often from the south for 10 months, from July 30 to June 6, with a peak percentage of 65% on January 1.

Wind Direction

Wind Direction in DeltanaSWSJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%southwesteastnorth
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Solar Energy

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.4 months, from April 24 to August 4, with an average daily incident shortwave energy per square meter above 4.5 kWh. The brightest day of the year is June 4, with an average of 5.7 kWh.

The darker period of the year lasts for 4.2 months, from October 16 to February 23, with an average daily incident shortwave energy per square meter below 1.2 kWh. The darkest day of the year is December 22, with an average of 0.1 kWh.

Average Daily Incident Shortwave Solar Energy

The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Deltana are 63.872 deg latitude, -145.218 deg longitude, and 1,230 ft elevation.

The topography within 2 miles of Deltana is essentially flat, with a maximum elevation change of 95 feet and an average elevation above sea level of 1,225 feet. Within 10 miles is essentially flat (4,495 feet). Within 50 miles also contains extreme variations in elevation (12,917 feet).

The area within 2 miles of Deltana is covered by trees (93%), within 10 miles by trees (42%) and cropland (21%), and within 50 miles by trees (39%) and shrubs (27%).

Data Sources

This report illustrates the typical weather in Deltana, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Deltana.

For each station, the records are corrected for the elevation difference between that station and Deltana according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at Deltana is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Deltana and a given station.

The stations contributing to this reconstruction are: Allen Army Air Field (95%, 28 kilometers, northwest) and Gulkana Airport (5%, 191 kilometers, south).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.