Average Weather in December in Hilmar-Irwin California, United States
In Hilmar-Irwin, the month of December is characterized by falling daily high temperatures, with daily highs decreasing by 5°F, from 60°F to 54°F over the course of the month, and rarely exceeding 66°F or dropping below 47°F. The lowest daily average high temperature is 54°F on December 29.
Daily low temperatures decrease by 2°F, from 41°F to 39°F, rarely falling below 30°F or exceeding 50°F. The lowest daily average low temperature is 39°F on December 30.
For reference, on July 17, the hottest day of the year, temperatures in Hilmar-Irwin typically range from 63°F to 95°F, while on December 30, the coldest day of the year, they range from 39°F to 54°F.
Average High and Low Temperature in December
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
The month of December in Hilmar-Irwin experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 46% to 51%.
The clearest day of the month is December 1, with clear, mostly clear, or partly cloudy conditions 54% of the time.
For reference, on February 6, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 52%, while on August 7, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 92%.
Cloud Cover in December
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Hilmar-Irwin, the chance of a wet day over the course of December is gradually increasing, starting the month at 20% and ending it at 23%.
For reference, the year's highest daily chance of a wet day is 29% on February 20, and its lowest chance is 0% on August 1.
Probability of Precipitation in December
The average sliding 31-day rainfall during December in Hilmar-Irwin is increasing, starting the month at 2.2 inches, when it rarely exceeds 4.6 inches or falls below 0.3 inches, and ending the month at 2.8 inches, when it rarely exceeds 5.8 inches or falls below 0.2 inches.
Average Monthly Rainfall in December
Over the course of December in Hilmar-Irwin, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 35 minutes of daylight and the longest day is December 1, with 9 hours, 46 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month in Hilmar-Irwin is 6:59 AM on December 1 and the latest sunrise is 18 minutes later at 7:17 AM on December 31.
The earliest sunset is 4:45 PM on December 6 and the latest sunset is 10 minutes later at 4:55 PM on December 31.
Daylight saving time is observed in Hilmar-Irwin 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, 45 minutes later, at 8:27 PM, while on December 21, the shortest day of the year, it rises at 7:14 AM and sets 9 hours, 35 minutes later, at 4:49 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in December
The chance that a given day will be muggy in Hilmar-Irwin is essentially constant during December, remaining around 0% throughout.
For reference, on July 22, 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.
Humidity Comfort Levels in December
The average hourly wind speed in Hilmar-Irwin is essentially constant during December, remaining within 0.1 miles per hour of 3.2 miles per hour throughout.
For reference, on June 6, the windiest day of the year, the daily average wind speed is 4.9 miles per hour, while on January 21, the calmest day of the year, the daily average wind speed is 3.0 miles per hour.
The highest daily average wind speed during December is 3.3 miles per hour on December 14.
Average Wind Speed in December
Wind Direction in December
The average daily incident shortwave solar energy in Hilmar-Irwin is essentially constant during December, remaining within 0.1 kWh of 2.4 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 2.3 kWh on December 26.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of Hilmar-Irwin are 37.405 deg latitude, -120.850 deg longitude, and 92 ft elevation.
The topography within 2 miles of Hilmar-Irwin is essentially flat, with a maximum elevation change of 33 feet and an average elevation above sea level of 92 feet. Within 10 miles is essentially flat (174 feet). Within 50 miles contains only modest variations in elevation (4,314 feet).
The area within 2 miles of Hilmar-Irwin is covered by cropland (92%), within 10 miles by cropland (92%), and within 50 miles by cropland (40%) and grassland (39%).
This report illustrates the typical weather in Hilmar-Irwin 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Hilmar-Irwin.
For each station, the records are corrected for the elevation difference between that station and Hilmar-Irwin 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 Hilmar-Irwin is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Hilmar-Irwin and a given station.
The stations contributing to this reconstruction are: Castle Airport (46%, 25 kilometers, east); Modesto City-County Airport (45%, 26 kilometers, north); and Hollister Municipal Airport (9%, 75 kilometers, southwest).
Time zones for aiports and weather stations are provided by AskGeo.com .