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Average Weather in December in Shafter California, United States

In Shafter, the month of December is characterized by falling daily high temperatures, with daily highs decreasing by 5°F, from 63°F to 58°F over the course of the month, and rarely exceeding 71°F or dropping below 49°F. The lowest daily average high temperature is 58°F on December 29.

Daily low temperatures increase by 6°F, from 41°F to 47°F, rarely falling below 34°F or exceeding 57°F.

For reference, on July 20, the hottest day of the year, temperatures in Shafter typically range from 69°F to 99°F, while on January 31, the coldest day of the year, they range from 41°F to 63°F.

Average High and Low Temperature in December

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 hourly average temperatures for the quarter of the year centered on December. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature in December

Average Hourly Temperature in December in Shafter12 AM4 AM8 AM12 PM4 PM8 PM12 AM181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930303131NovJanchillycoldcoolcomfortable
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.


The month of December in Shafter experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 37% to 42%. The highest chance of overcast or mostly cloudy conditions is 43% on December 28.

The clearest day of the month is December 1, with clear, mostly clear, or partly cloudy conditions 63% of the time.

For reference, on February 17, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 43%, while on August 9, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 92%.

Cloud Cover in December

Cloud Cover in December in Shafter0%10%20%30%40%50%60%70%80%90%100%181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930303131NovJanDec 2843%Dec 2843%Dec 137%Dec 137%Dec 1138%Dec 1138%overcastmostly cloudypartly cloudymostly clearclear
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.


A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Shafter, the chance of a wet day over the course of December is very rapidly decreasing, starting the month at 14% and ending it at 3%.

For reference, the year's highest daily chance of a wet day is 23% on February 21, and its lowest chance is 0% on June 27.

Probability of Precipitation in December

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).


Over the course of December in Shafter, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 45 minutes of daylight and the longest day is December 1, with 9 hours, 56 minutes of daylight.

Hours of Daylight and Twilight in December

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 of the month in Shafter is 6:48 AM on December 1 and the latest sunrise is 18 minutes later at 7:06 AM on December 31.

The earliest sunset is 4:43 PM on December 5 and the latest sunset is 11 minutes later at 4:54 PM on December 31.

Daylight saving time is observed in Shafter during 2017, but it neither starts nor ends during December, so the entire month is in standard time.

For reference, on June 21, the longest day of the year, the Sun rises at 5:42 AM and sets 14 hours, 34 minutes later, at 8:15 PM, while on December 21, the shortest day of the year, it rises at 7:02 AM and sets 9 hours, 45 minutes later, at 4:48 PM.

Sunrise & Sunset with Twilight and Daylight Saving Time in December

The solar day over the course of December. 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.


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 chance that a given day will be muggy in Shafter is essentially constant during December, remaining around 0% throughout.

For reference, on August 30, the muggiest day of the year, there are muggy conditions 1% of the time, while on November 2, the least muggy day of the year, there are muggy conditions 0% of the time.

Humidity Comfort Levels in December

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.


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 Shafter is essentially constant during December, remaining around 2.7 miles per hour throughout.

For reference, on June 1, the windiest day of the year, the daily average wind speed is 3.8 miles per hour, while on November 8, the calmest day of the year, the daily average wind speed is 2.6 miles per hour.

The highest daily average wind speed during December is 2.8 miles per hour on December 23.

Average Wind Speed in December

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
The hourly average wind direction in Shafter throughout December is predominantly from the south, with a peak proportion of 39% on December 31.

Wind Direction in December

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 in Shafter is essentially constant during December, remaining within 0.1 kWh of 2.8 kWh throughout.

The lowest average daily incident shortwave solar energy during December is 2.7 kWh on December 26.

Average Daily Incident Shortwave Solar Energy in December

Average Daily Incident Shortwave Solar Energy in December in Shafter0.0 kWh0.5 kWh1.0 kWh1.5 kWh2.0 kWh2.5 kWh3.0 kWh3.5 kWh4.0 kWh4.5 kWh181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930303131NovJanDec 262.7 kWhDec 262.7 kWhDec 13.0 kWhDec 13.0 kWhDec 112.8 kWhDec 112.8 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.


For the purposes of this report, the geographical coordinates of Shafter are 35.501 deg latitude, -119.272 deg longitude, and 344 ft elevation.

The topography within 2 miles of Shafter is essentially flat, with a maximum elevation change of 52 feet and an average elevation above sea level of 347 feet. Within 10 miles is essentially flat (407 feet). Within 50 miles contains only modest variations in elevation (8,638 feet).

The area within 2 miles of Shafter is covered by cropland (90%), within 10 miles by cropland (91%), and within 50 miles by grassland (41%) and cropland (35%).

Data Sources

This report illustrates the typical weather in Shafter year round, 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 6 weather stations near enough to contribute to our estimation of the temperature and dew point in Shafter.

For each station, the records are corrected for the elevation difference between that station and Shafter 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 Shafter is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Shafter and a given station.

The stations contributing to this reconstruction are: Meadows Field (67%, 21 kilometers, east); Porterville Municipal Airport (14%, 62 kilometers, north); Santa Ynez Airport (4.9%, 124 kilometers, southwest); Paso Robles Municipal Airport (4.8%, 124 kilometers, west); Santa Maria Airport (4.7%, 126 kilometers, southwest); and San Luis Obispo County Airport (4.6%, 128 kilometers, west).

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.