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Average Weather in August in San Diego California, United States

In San Diego, the month of August is characterized by essentially constant daily high temperatures, with daily highs around 77°F throughout the month, rarely exceeding 83°F or dropping below 72°F. The highest daily average high temperature is 77°F on August 26.

Daily low temperatures are around 68°F, rarely falling below 64°F or exceeding 72°F. The highest daily average low temperature is 68°F on August 25.

For reference, on August 26, the hottest day of the year, temperatures in San Diego typically range from 68°F to 77°F, while on December 28, the coldest day of the year, they range from 50°F to 65°F.

Average High and Low Temperature in August

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on August. 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 August

Average Hourly Temperature in August in San Diego18152229112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM4 AM8 AM12 PM4 PM8 PM12 AMJulSepwarmcomfortable
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < chilly < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Clouds

The month of August in San Diego 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 clearest day of the month is August 31, with clear, mostly clear, or partly cloudy conditions 90% of the time.

For reference, on February 20, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 43%, while on September 10, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 91%.

Cloud Cover Categories in August

Cloud Cover Categories in August in San Diego1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JulSepAug 186%Aug 186%Aug 3190%Aug 3190%Aug 1187%Aug 1187%Aug 2189%Aug 2189%clearmostly clearovercastpartly cloudymostly cloudy
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In San Diego, the chance of a wet day over the course of August is essentially constant, remaining around 2% throughout.

For reference, the year's highest daily chance of a wet day is 20% on February 22, and its lowest chance is 0% on June 27.

Probability of Precipitation in August

The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

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 August in San Diego is essentially constant, remaining about 0.1 inches throughout, and rarely exceeding 0.3 inches.

Average Monthly Rainfall in August

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Sun

Over the course of August in San Diego, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 53 minutes, implying an average daily decrease of 1 minute, 45 seconds, and weekly decrease of 12 minutes, 15 seconds.

The shortest day of the month is August 31, with 12 hours, 51 minutes of daylight and the longest day is August 1, with 13 hours, 44 minutes of daylight.

Hours of Daylight and Twilight in August

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise of the month in San Diego is 6:02 AM on August 1 and the latest sunrise is 20 minutes later at 6:22 AM on August 31.

The latest sunset is 7:46 PM on August 1 and the earliest sunset is 32 minutes earlier at 7:14 PM on August 31.

Daylight saving time is observed in San Diego during 2017, but it neither starts nor ends during August, so the entire month is in daylight saving time.

For reference, on June 21, the longest day of the year, the Sun rises at 5:41 AM and sets 14 hours, 18 minutes later, at 7:59 PM, while on December 21, the shortest day of the year, it rises at 6:47 AM and sets 9 hours, 60 minutes later, at 4:46 PM.

Sunrise & Sunset with Twilight in August

The solar day over the course of August. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

Humidity

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 San Diego is increasing during August, rising from 15% to 21% over the course of the month.

The highest chance of a muggy day during August is 23% on August 27.

For reference, on August 27, the muggiest day of the year, there are muggy conditions 23% 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 August

Humidity Comfort Levels in August in San Diego1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%10%20%30%40%50%60%70%80%90%100%JulSepAug 2723%Aug 2723%Aug 115%Aug 115%Aug 1117%Aug 1117%muggymuggydrydryhumidhumidcomfortablecomfortable
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

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 San Diego is essentially constant during August, remaining around 3.2 miles per hour throughout.

For reference, on December 11, the windiest day of the year, the daily average wind speed is 4.3 miles per hour, while on August 23, the calmest day of the year, the daily average wind speed is 3.2 miles per hour.

Average Wind Speed in August

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
The hourly average wind direction in San Diego throughout August is predominantly from the west, with a peak proportion of 75% on August 1.

Wind Direction in August

Wind Direction in August in San Diego1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JulSepwestnorthsoutheast
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

San Diego 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 San Diego is essentially constant during August, remaining around 69°F throughout.

The highest average surface water temperature during August is 70°F on August 27.

Average Water Temperature in August

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

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 San Diego is gradually decreasing during August, falling by 0.8 kWh, from 7.8 kWh to 7.0 kWh, over the course of the month.

Average Daily Incident Shortwave Solar Energy in August

The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of San Diego are 32.715 deg latitude, -117.157 deg longitude, and 33 ft elevation.

The topography within 2 miles of San Diego contains only modest variations in elevation, with a maximum elevation change of 305 feet and an average elevation above sea level of 93 feet. Within 10 miles contains only modest variations in elevation (1,552 feet). Within 50 miles contains very significant variations in elevation (6,483 feet).

The area within 2 miles of San Diego is covered by artificial surfaces (72%) and water (21%), within 10 miles by artificial surfaces (56%) and water (37%), and within 50 miles by water (48%) and shrubs (33%).

Data Sources

This report illustrates the typical weather in San Diego 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 San Diego.

For each station, the records are corrected for the elevation difference between that station and San Diego 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 San Diego is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between San Diego and a given station.

The stations contributing to this reconstruction are: San Diego International Airport (58%, 3.2 kilometers, northwest); Naval Air Station North Island (37%, 4.4 kilometers, southwest); and Ream Field (4.9%, 17 kilometers, south).

Other Data

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.