Average Weather in July in Cool California, United States
The highest daily average high temperature is 93°F on July 28.
Daily low temperatures increase by 3°F, from 64°F to 67°F, rarely falling below 56°F or exceeding 74°F. The highest daily average low temperature is 67°F on July 26.
For reference, on July 28, the hottest day of the year, temperatures in Cool typically range from 67°F to 93°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 July
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on July. 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 July
The month of July in Cool experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 12% throughout the month. The lowest chance of overcast or mostly cloudy conditions is 10% on July 21.
The clearest day of the month is July 21, with clear, mostly clear, or partly cloudy conditions 90% of the time.
For reference, on February 21, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 59%, while on July 21, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 90%.
Cloud Cover Categories in July
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Cool, the chance of a wet day over the course of July is essentially constant, remaining around 1% throughout.
For reference, the year's highest daily chance of a wet day is 34% on February 20, and its lowest chance is 0% on July 21.
Probability of Precipitation in July
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 July in Cool is essentially constant, remaining about 0.1 inches throughout, and rarely exceeding 0.6 inches or falling below -0.0 inches.
The lowest average 31-day accumulation is 0.0 inches on July 30.
Average Monthly Rainfall in July
Over the course of July in Cool, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 39 minutes, implying an average daily decrease of 1 minute, 19 seconds, and weekly decrease of 9 minutes, 10 seconds.
The shortest day of the month is July 31, with 14 hours, 11 minutes of daylight and the longest day is July 1, with 14 hours, 51 minutes of daylight.
Hours of Daylight and Twilight in July
The earliest sunrise of the month in Cool is 5:42 AM on July 1 and the latest sunrise is 22 minutes later at 6:04 AM on July 31.
The latest sunset is 8:33 PM on July 1 and the earliest sunset is 17 minutes earlier at 8:15 PM on July 31.
Daylight saving time is observed in Cool during 2017, but it neither starts nor ends during July, so the entire month is in daylight saving time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:39 AM and sets 14 hours, 54 minutes later, at 8:32 PM, while on December 21, the shortest day of the year, it rises at 7:19 AM and sets 9 hours, 26 minutes later, at 4:45 PM.
Sunrise & Sunset with Twilight in July
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 Cool is essentially constant during July, remaining around 0% throughout.
For reference, on September 10, 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 July
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 Cool is essentially constant during July, remaining around 5.8 miles per hour throughout.
For reference, on December 18, the windiest day of the year, the daily average wind speed is 6.3 miles per hour, while on October 3, the calmest day of the year, the daily average wind speed is 5.2 miles per hour.
The highest daily average wind speed during July is 5.9 miles per hour on July 20.
Average Wind Speed in July
Wind Direction in July
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 in Cool typically lasts for 12 months (354 days), from around January 9 to around December 28, rarely starting after March 1, or ending before November 25.
The month of July in Cool is reliably fully within the growing season.
Time Spent in Various Temperature Bands and the Growing Season in July
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 in Cool are rapidly increasing during July, increasing by 802°F, from 1,612°F to 2,414°F, over the course of the month.
Growing Degree Days in July
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 Cool is essentially constant during July, remaining within 0.2 kWh of 8.3 kWh throughout.
The highest average daily incident shortwave solar energy during July is 8.5 kWh on July 1.
Average Daily Incident Shortwave Solar Energy in July
For the purposes of this report, the geographical coordinates of Cool are 38.887 deg latitude, -121.015 deg longitude, and 1,381 ft elevation.
The topography within 2 miles of Cool contains very significant variations in elevation, with a maximum elevation change of 1,257 feet and an average elevation above sea level of 1,431 feet. Within 10 miles contains very significant variations in elevation (2,464 feet). Within 50 miles contains large variations in elevation (9,915 feet).
The area within 2 miles of Cool is covered by grassland (53%), shrubs (26%), and trees (20%), within 10 miles by shrubs (39%) and grassland (30%), and within 50 miles by trees (35%) and cropland (21%).
This report illustrates the typical weather in Cool 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 Cool.
For each station, the records are corrected for the elevation difference between that station and Cool 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 Cool is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Cool and a given station.
The stations contributing to this reconstruction are: Auburn Municipal Airport (85%, 10 kilometers, northwest); Placerville Airport (9%, 30 kilometers, southeast); and Sacramento Mather Airport (6%, 43 kilometers, southwest).
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.
The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.
We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.
We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.