Average Weather in Arnold California, United States
In Arnold, the summers are warm, arid, and mostly clear and the winters are long, very cold, wet, and partly cloudy. Over the course of the year, the temperature typically varies from 30°F to 84°F and is rarely below 21°F or above 91°F.
Based on the tourism score, the best time of year to visit Arnold for warm-weather activities is from late June to early September.
The warm season lasts for 3.2 months, from June 13 to September 19, with an average daily high temperature above 76°F. The hottest day of the year is July 28, with an average high of 84°F and low of 55°F.
The cold season lasts for 3.9 months, from November 18 to March 15, with an average daily high temperature below 54°F. The coldest day of the year is December 25, with an average low of 30°F and high of 47°F.
Average High and Low Temperature
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
In Arnold, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year in Arnold begins around May 21 and lasts for 5.1 months, ending around October 25. On July 29, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 90% of the time, and overcast or mostly cloudy 10% of the time.
The cloudier part of the year begins around October 25 and lasts for 6.9 months, ending around May 21. On February 21, the cloudiest day of the year, the sky is overcast or mostly cloudy 57% of the time, and clear, mostly clear, or partly cloudy 43% of the time.
Cloud Cover Categories
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Arnold varies significantly throughout the year.
The wetter season lasts 5.8 months, from October 30 to April 23, with a greater than 17% chance of a given day being a wet day. The chance of a wet day peaks at 33% on February 21.
The drier season lasts 6.2 months, from April 23 to October 30. The smallest chance of a wet day is 1% on August 3.
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 throughout the year is rain alone, with a peak probability of 26% on February 21.
Daily Chance of Precipitation
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. Arnold experiences extreme seasonal variation in monthly rainfall.
The rainy period of the year lasts for 8.4 months, from September 22 to June 5, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around February 17, with an average total accumulation of 4.4 inches.
The rainless period of the year lasts for 3.6 months, from June 5 to September 22. The least rain falls around August 5, with an average total accumulation of 0.0 inches.
Average Monthly Rainfall
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. Arnold experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 4.9 months, from November 12 to April 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 December 31, with an average total liquid-equivalent accumulation of 0.4 inches.
The snowless period of the year lasts for 7.1 months, from April 10 to November 12. The least snow falls around August 2, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Arnold varies significantly over the course of the year. In 2019, the shortest day is December 21, with 9 hours, 30 minutes of daylight; the longest day is June 21, with 14 hours, 50 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:37 AM on June 14, and the latest sunrise is 1 hour, 51 minutes later at 7:28 AM on November 2. The earliest sunset is at 4:40 PM on December 7, and the latest sunset is 3 hours, 48 minutes later at 8:28 PM on June 28.
Daylight saving time (DST) is observed in Arnold during 2019, starting in the spring on March 10, lasting 7.8 months, and ending in the fall on November 3.
Sunrise & Sunset with Twilight and Daylight Saving Time
The perceived humidity level in Arnold, 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
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
Average Wind Speed
The predominant average hourly wind direction in Arnold varies throughout the year.
The wind is most often from the south for 2.0 months, from February 4 to April 4 and for 2.4 weeks, from November 18 to December 5, with a peak percentage of 41% on February 20. The wind is most often from the west for 5.8 months, from April 4 to September 27, with a peak percentage of 48% on June 15. The wind is most often from the east for 1.7 months, from September 27 to November 18 and for 2.0 months, from December 5 to February 4, with a peak percentage of 37% on October 22.
Best Time of Year to Visit
To characterize how pleasant the weather is in Arnold throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Arnold for general outdoor tourist activities is from late June to early September, with a peak score in the third week of July.
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Arnold for hot-weather activities is from early July to late August, with a peak score in the third week of July.
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
The growing season in Arnold typically lasts for 6.2 months (191 days), from around April 22 to around October 30, rarely starting before March 26 or after May 20, and rarely ending before October 5 or after November 22.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Arnold should appear around April 5, only rarely appearing before March 17 or after May 1.
Growing Degree Days
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 3.5 months, from May 9 to August 23, with an average daily incident shortwave energy per square meter above 7.3 kWh. The brightest day of the year is June 27, with an average of 8.6 kWh.
The darker period of the year lasts for 3.4 months, from November 3 to February 17, with an average daily incident shortwave energy per square meter below 3.5 kWh. The darkest day of the year is December 21, with an average of 2.3 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Arnold are 38.255 deg latitude, -120.351 deg longitude, and 4,045 ft elevation.
The topography within 2 miles of Arnold contains very significant variations in elevation, with a maximum elevation change of 1,204 feet and an average elevation above sea level of 4,042 feet. Within 10 miles contains very significant variations in elevation (5,289 feet). Within 50 miles also contains extreme variations in elevation (11,598 feet).
The area within 2 miles of Arnold is covered by trees (100%), within 10 miles by trees (65%) and shrubs (34%), and within 50 miles by trees (34%) and shrubs (31%).
This report illustrates the typical weather in Arnold, 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 5 weather stations near enough to contribute to our estimation of the temperature and dew point in Arnold.
For each station, the records are corrected for the elevation difference between that station and Arnold 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 Arnold is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Arnold and a given station.
The stations contributing to this reconstruction are: Placerville Airport (34%, 62 kilometers, northwest); Bridgeport Sonora Junction (20%, 74 kilometers, east); Lake Tahoe Airport (21%, 78 kilometers, northeast); Stockton Metropolitan Airport (12%, 87 kilometers, southwest); and Modesto City-County Airport (12%, 88 kilometers, southwest).
Time zones for aiports and weather stations are provided by AskGeo.com .