Average Weather In December For Fresno, California, USA
Location
This report describes the typical weather at the Fresno Yosemite International Airport (Fresno, California, United States) weather station over the course of an average December. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
Fresno, California has a cold semi-arid steppe climate. The area within 25 mi of this station is covered by grasslands (57%), croplands (28%), forests (11%), and built-up areas (2%).
Temperature
The month of December is characterized by falling daily high temperatures, with daily highs decreasing from 59°F to 53°F over the course of the month, exceeding 66°F or dropping below 44°F only one day in ten.
Daily High and Low Temperature in December
The daily average low (blue) and high (red) temperature with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).
Fraction of Time Spent in Various Temperature Bands in December
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
Over the course of December, the length of the day is essentially constant. The shortest day of the month is December 14 with 9:40 hours of daylight; the longest day is December 1 with 9:49 hours of daylight.
Daily Hours of Daylight and Twilight in December
The number of hours during which the Sun is visible (black line), with various degrees of daylight, twilight, and night, indicated by the color bands. From bottom (most yellow) to top (most gray): full daylight, solar twilight (Sun is visible but less than 6° from the horizon), civil twilight (Sun is not visible but is less than 6° below the horizon), nautical twilight (Sun is between 6° and 12° below the horizon), astronomical twilight (Sun is between 12° and 18° below the horizon), and full night.
The earliest sunrise is at 6:53am on December 1; the latest sunset is at 4:53pm on December 31; the latest sunrise is at 7:12am on December 29; the earliest sunset is at 4:42pm on December 4.
Daylight savings time is observed in 2012 but it neither starts nor ends in December, so the entire month is in standard time.
Daily Sunrise & Sunset with Twilight and Daylight Savings Time in December
The solar day over the course of the year 2012 . From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (solar, civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight savings time are indicated by the "DST" labels.
Clouds
The median cloud cover ranges from 60% (partly cloudy) to 84% (mostly cloudy). The trend is for the sky to be becoming rapidly cloudier with the median cloud cover increasing by 24% from the start to the end of the month.
Median Cloud Cover in December
The median daily cloud cover (black line) with percentile bands (inner band from 40th to 60th percentile, outer band from 25th to 75th percentile).
On December 1, the clearest day of the month, the sky is clear, mostly clear, or partly cloudy 53% of the time, and overcast or mostly cloudy 45% of the time.
On December 30, the cloudiest day of the month, the sky is overcast, mostly cloudy, or partly cloudy 68% of the time, and clear or mostly clear 31% of the time.
Cloud Cover Types in December
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 of the United States clear skies are often reported ambiguously, leading them to be lumped in with the missing data.
Precipitation
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around December 31, occurring in 34% of days. Precipitation is least likely around December 1, occurring in 28% of days.
Probability of Precipitation at Some Point in the Day in December
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.
Throughout December, the most common forms of precipitation are light rain, moderate rain, and drizzle.
Light rain is the most severe precipitation observed during 42% of those days with precipitation. It is most likely around December 10, when it is observed during 14% of all days.
Moderate rain is the most severe precipitation observed during 39% of those days with precipitation. It is most likely around December 27, when it is observed during 13% of all days.
Drizzle is the most severe precipitation observed during 12% of those days with precipitation. It is most likely around December 31, when it is observed during 4% of all days.
Types of Precipitation Throughout December
Relative frequency of various types of precipitation over the course of a typical December.
Snow
Either snow is exceptionally unlikely to fall at this location in December or this station does not reliably report precipitation types.
Humidity
The relative humidity typically ranges from 54% (mildly humid) to 95% (very humid) over the course of a typical December, rarely dropping below 33% (comfortable) and reaching as high as 100% (very humid).
The air is driest around December 1, at which time the relative humidity drops below 65% (mildly humid) three days out of four; it is most humid around December 15, rising above 93% (very humid) three days out of four.
Relative Humidity in December
The average daily high (blue) and low (brown) relative humidity with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).
Dew Point
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 December, the dew point typically varies from 35°F (dry) to 45°F (dry) and is rarely below 27°F (dry) or above 52°F (very comfortable).
Dew Point in December
The daily average low (blue) and high (red) dew point with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).
Wind
Over the course of December typical wind speeds vary from 0 mph to 9 mph (calm to gentle breeze), rarely exceeding 15 mph (moderate breeze).
The highest average wind speed of 4 mph (light breeze) occurs around December 28, at which time the average daily maximum wind speed is 9 mph (gentle breeze).
The lowest average wind speed of 4 mph (light breeze) occurs around December 2, at which time the average daily maximum wind speed is 8 mph (gentle breeze).
Wind Speed in December
The average daily minimum (red), maximum (green), and average (black) wind speed with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).
Wind Directions in December
The fraction of time spent with the wind blowing from the various directions over the entire year. Values do not sum to 100% because the wind direction is undefined when the wind speed is zero.
Fraction of Time Spent with Various Wind Directions in December
The fraction of time spent with the wind blowing from the various directions on a daily basis. Stacked values do not always sum to 100% because the wind direction is undefined when the wind speed is zero.