December Weather at Ukiah Municipal Airport United States

Daily high temperatures decrease by 3°F, from 57°F to 55°F, rarely falling below 47°F or exceeding 65°F. The lowest daily average high temperature is 54°F on December 26.

Daily low temperatures decrease by 2°F, from 39°F to 36°F, rarely falling below 27°F or exceeding 49°F. The lowest daily average low temperature is 36°F on December 31.

For reference, on July 28, the hottest day of the year, temperatures at Ukiah Municipal Airport typically range from 56°F to 93°F, while on December 31, the coldest day of the year, they range from 36°F to 55°F.

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.

Santiago, Chile (6,044 miles away); Salar, Spain (5,908 miles); and Wangaratta, Australia (7,767 miles) are the far-away foreign places with temperatures most similar to Ukiah Municipal Airport (view comparison).

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The month of December at Ukiah Municipal Airport experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 61% throughout the month.

The clearest day of the month is December 7, with clear, mostly clear, or partly cloudy conditions 41% of the time.

For reference, on January 10, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 64%, while on July 31, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 91%.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. At Ukiah Municipal Airport, the chance of a wet day over the course of December is essentially constant, remaining around 34% throughout.

For reference, the year's highest daily chance of a wet day is 37% on February 28, and its lowest chance is 0% on August 2.

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during December at Ukiah Municipal Airport is gradually increasing, starting the month at 6.3 inches, when it rarely exceeds 12.8 inches or falls below 1.3 inches, and ending the month at 6.7 inches, when it rarely exceeds 12.7 inches or falls below 0.7 inches.

The highest average 31-day accumulation is 6.8 inches on December 15.

Over the course of December at Ukiah Municipal Airport, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 25 minutes of daylight and the longest day is December 1, with 9 hours, 37 minutes of daylight.

The earliest sunrise of the month at Ukiah Municipal Airport is 7:13 AM on December 1 and the latest sunrise is 18 minutes later at 7:32 AM on December 31.

The earliest sunset is 4:49 PM on December 6 and the latest sunset is 11 minutes later at 5:00 PM on December 31.

Daylight saving time is observed at Ukiah Municipal Airport during 2024, but it neither starts nor ends during December, so the entire month is in daylight saving time.

For reference, on June 20, the longest day of the year, the Sun rises at 5:46 AM and sets 14 hours, 55 minutes later, at 8:42 PM, while on December 21, the shortest day of the year, it rises at 7:28 AM and sets 9 hours, 25 minutes later, at 4:53 PM.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

The figure below presents a compact representation of key lunar data for December 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

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 at Ukiah Municipal Airport is essentially constant during December, remaining around 0% throughout.

For reference, on July 12, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.

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 at Ukiah Municipal Airport is essentially constant during December, remaining within 0.1 miles per hour of 5.0 miles per hour throughout.

For reference, on June 5, the windiest day of the year, the daily average wind speed is 5.7 miles per hour, while on September 20, the calmest day of the year, the daily average wind speed is 4.6 miles per hour.

The highest daily average wind speed during December is 5.1 miles per hour on December 12.

The hourly average wind direction at Ukiah Municipal Airport throughout December is predominantly from the north, with a peak proportion of 39% on December 7.

Ukiah Municipal Airport is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average surface water temperature at Ukiah Municipal Airport is essentially constant during December, remaining around 54°F throughout.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season at Ukiah Municipal Airport typically lasts for 8.5 months (262 days), from around March 2 to around November 19, rarely starting before January 28 or after April 6, and rarely ending before October 29 or after December 10.

The month of December at Ukiah Municipal Airport is more likely than not fully outside of the growing season, with the chance that a given day is in the growing season decreasing from 22% to 3% over the course of the month.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

The average accumulated growing degree days at Ukiah Municipal Airport are gradually increasing during December, increasing by 36°F, from 3,497°F to 3,533°F, over the course of the month.

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 at Ukiah Municipal Airport is essentially constant during December, remaining within 0.1 kWh of 1.9 kWh throughout.

The lowest average daily incident shortwave solar energy during December is 1.8 kWh on December 25.

For the purposes of this report, the geographical coordinates of Ukiah Municipal Airport are 39.126 deg latitude, -123.202 deg longitude, and 610 ft elevation.

The topography within 2 miles of Ukiah Municipal Airport contains very significant variations in elevation, with a maximum elevation change of 1,916 feet and an average elevation above sea level of 842 feet. Within 10 miles contains very significant variations in elevation (3,409 feet). Within 50 miles also contains extreme variations in elevation (7,362 feet).

The area within 2 miles of Ukiah Municipal Airport is covered by cropland (38%), artificial surfaces (29%), and shrubs (27%), within 10 miles by shrubs (62%) and trees (18%), and within 50 miles by shrubs (37%) and trees (28%).