Average Weather in July in Black Point-Green Point California, United States
Daily high temperatures are around 81°F, rarely falling below 71°F or exceeding 92°F.
Daily low temperatures are around 52°F, rarely falling below 48°F or exceeding 57°F. The highest daily average low temperature is 53°F on July 31.
For reference, on August 24, the hottest day of the year, temperatures in Black Point-Green Point typically range from 52°F to 82°F, while on December 31, the coldest day of the year, they range from 39°F to 55°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 Black Point-Green Point experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 10% throughout the month. The lowest chance of overcast or mostly cloudy conditions is 8% on July 20.
The clearest day of the month is July 20, with clear, mostly clear, or partly cloudy conditions 92% of the time.
For reference, on January 11, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 56%, while on July 20, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 92%.
Cloud Cover Categories in July
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Black Point-Green Point, 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 32% on February 20, and its lowest chance is 0% on July 28.
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 Black Point-Green Point is essentially constant, remaining about 0.0 inches throughout, and rarely exceeding 0.3 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 Black Point-Green Point, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 38 minutes, implying an average daily decrease of 1 minute, 16 seconds, and weekly decrease of 8 minutes, 49 seconds.
The shortest day of the month is July 31, with 14 hours, 8 minutes of daylight and the longest day is July 1, with 14 hours, 46 minutes of daylight.
Hours of Daylight and Twilight in July
The earliest sunrise of the month in Black Point-Green Point is 5:50 AM on July 1 and the latest sunrise is 21 minutes later at 6:12 AM on July 31.
The latest sunset is 8:36 PM on July 1 and the earliest sunset is 17 minutes earlier at 8:20 PM on July 31.
Daylight saving time is observed in Black Point-Green Point during 2018, 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 5:47 AM and sets 14 hours, 49 minutes later, at 8:36 PM, while on December 21, the shortest day of the year, it rises at 7:22 AM and sets 9 hours, 31 minutes later, at 4:53 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 Black Point-Green Point is essentially constant during July, remaining around 0% throughout.
For reference, on July 6, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 18, 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 Black Point-Green Point is essentially constant during July, remaining within 0.2 miles per hour of 7.7 miles per hour throughout.
For reference, on May 30, the windiest day of the year, the daily average wind speed is 8.4 miles per hour, while on October 21, the calmest day of the year, the daily average wind speed is 6.6 miles per hour.
Average Wind Speed in July
Wind Direction in July
Black Point-Green Point 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 in Black Point-Green Point is gradually increasing during July, rising by 2°F, from 54°F to 56°F, over the course of the month.
Average Water Temperature 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 Black Point-Green Point typically lasts for 10 months (313 days), from around January 29 to around December 8, rarely starting after February 28, or ending before November 16.
The month of July in Black Point-Green Point 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 Black Point-Green Point are increasing during July, increasing by 421°F, from 1,180°F to 1,601°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 Black Point-Green Point is essentially constant during July, remaining within 0.2 kWh of 8.2 kWh throughout.
Average Daily Incident Shortwave Solar Energy in July
For the purposes of this report, the geographical coordinates of Black Point-Green Point are 38.115 deg latitude, -122.513 deg longitude, and 3 ft elevation.
The topography within 2 miles of Black Point-Green Point contains only modest variations in elevation, with a maximum elevation change of 361 feet and an average elevation above sea level of 31 feet. Within 10 miles contains only modest variations in elevation (1,880 feet). Within 50 miles contains very significant variations in elevation (4,698 feet).
The area within 2 miles of Black Point-Green Point is covered by cropland (39%) and herbaceous vegetation (37%), within 10 miles by grassland (32%) and water (22%), and within 50 miles by water (34%) and grassland (20%).
This report illustrates the typical weather in Black Point-Green Point 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 Black Point-Green Point.
For each station, the records are corrected for the elevation difference between that station and Black Point-Green Point 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 Black Point-Green Point is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Black Point-Green Point and a given station.
The stations contributing to this reconstruction are: Gnoss Field (88%, 5.0 kilometers, northwest); Napa County Airport (9%, 23 kilometers, northeast); and Naval Air Station Alameda (historical) (3.2%, 46 kilometers, south).
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.