1. WeatherSpark.com
  2. Puerto Rico
  3. Dorado
  4. San Antonio

Average Weather in August in San Antonio Puerto Rico

Daily high temperatures are around 89°F, rarely falling below 86°F or exceeding 91°F. The highest daily average high temperature is 89°F on August 25.

Daily low temperatures are around 77°F, rarely falling below 75°F or exceeding 79°F. The highest daily average low temperature is 77°F on August 7.

For reference, on August 5, the hottest day of the year, temperatures in San Antonio typically range from 77°F to 89°F, while on January 25, the coldest day of the year, they range from 70°F to 83°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 Antonio18152229112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMJulSepwarmwarmhot
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Zanzibar, Tanzania (7,375 miles away) and Mtakoudja, Comoros (7,789 miles) are the far-away foreign places with temperatures most similar to San Antonio (view comparison).

Clouds

The month of August in San Antonio experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 61% to 66%.

The clearest day of the month is August 1, with clear, mostly clear, or partly cloudy conditions 39% of the time.

For reference, on May 30, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 73%, while on January 11, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 82%.

Cloud Cover Categories in August

Cloud Cover Categories in August in San Antonio1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JulSepAug 139%Aug 139%Aug 3134%Aug 3134%Aug 1138%Aug 1138%Aug 2137%Aug 2137%mostly clearpartly cloudymostly cloudyovercastclear
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In San Antonio, the chance of a wet day over the course of August is very rapidly increasing, starting the month at 35% and ending it at 47%.

For reference, the year's highest daily chance of a wet day is 51% on September 27, and its lowest chance is 20% on January 9.

Probability of Precipitation in August

Probability of Precipitation in August in San Antonio1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%5%5%10%10%15%15%20%20%25%25%30%30%35%35%40%40%45%45%50%50%55%55%JulSepAug 135%Aug 135%Aug 3147%Aug 3147%Aug 1140%Aug 1140%Aug 2142%Aug 2142%rain
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 Antonio is rapidly increasing, starting the month at 2.5 inches, when it rarely exceeds 5.3 inches or falls below 0.8 inches, and ending the month at 3.9 inches, when it rarely exceeds 7.8 inches or falls below 1.0 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 Antonio, the length of the day is gradually decreasing. From the start to the end of the month, the length of the day decreases by 27 minutes, implying an average daily decrease of 54 seconds, and weekly decrease of 6 minutes, 20 seconds.

The shortest day of the month is August 31, with 12 hours, 30 minutes of daylight and the longest day is August 1, with 12 hours, 57 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 Antonio is 6:03 AM on August 1 and the latest sunrise is 7 minutes later at 6:10 AM on August 31.

The latest sunset is 6:59 PM on August 1 and the earliest sunset is 20 minutes earlier at 6:40 PM on August 31.

Daylight saving time is not observed in San Antonio during 2021.

For reference, on June 21, the longest day of the year, the Sun rises at 5:49 AM and sets 13 hours, 14 minutes later, at 7:04 PM, while on December 21, the shortest day of the year, it rises at 6:52 AM and sets 11 hours, 1 minute later, at 5:54 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.

Moon

The figure below presents a compact representation of key lunar data for August 2021. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

Moon Rise, Set & Phases in August

Moon in San Antonio18152229112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMJulSepJul 99:17 PMJul 99:17 PMJul 2310:38 PMJul 2310:38 PMAug 89:51 AMAug 89:51 AMAug 228:03 AMAug 228:03 AMSep 68:52 PMSep 68:52 PMSep 207:55 PMSep 207:55 PM5:22 AM5:22 AM7:04 PM7:04 PM7:01 PM7:01 PM6:21 AM6:21 AM5:59 AM5:59 AM7:22 PM7:22 PM6:33 PM6:33 PM6:08 AM6:08 AM5:41 AM5:41 AM6:41 PM6:41 PM6:30 PM6:30 PM6:41 AM6:41 AM
The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.

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 Antonio is essentially constant during August, remaining around 100% throughout.

For reference, on June 1, the muggiest day of the year, there are muggy conditions 100% of the time, while on March 6, the least muggy day of the year, there are muggy conditions 79% of the time.

Humidity Comfort Levels in August

Humidity Comfort Levels in August in San Antonio1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%JulSepAug 1100%Aug 1100%Aug 31100%Aug 31100%Aug 11100%Aug 11100%Aug 21100%Aug 21100%miserablemiserableoppressiveoppressivemuggymuggy
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

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 Antonio is decreasing during August, decreasing from 12.0 miles per hour to 10.7 miles per hour over the course of the month.

For reference, on July 14, the windiest day of the year, the daily average wind speed is 12.3 miles per hour, while on October 10, the calmest day of the year, the daily average wind speed is 9.1 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 Antonio throughout August is predominantly from the east, with a peak proportion of 98% on August 1.

Wind Direction in August

Wind Direction in August in San Antonio1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%20%80%40%60%60%40%80%20%100%0%JulSepeastsouth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 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 Antonio 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 Antonio is essentially constant during August, remaining around 83°F throughout.

Average Water Temperature in August

Average Water Temperature in August in San Antonio18152229112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313180.5°F80.5°F81.0°F81.0°F81.5°F81.5°F82.0°F82.0°F82.5°F82.5°F83.0°F83.0°F83.5°F83.5°F84.0°F84.0°F84.5°F84.5°F85.0°F85.0°F85.5°F85.5°FJulSepAug 183°FAug 183°FAug 3184°FAug 3184°FAug 1183°FAug 1183°FAug 2183°FAug 2183°F
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Growing Season

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).

Temperatures in San Antonio are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.

Time Spent in Various Temperature Bands and the Growing Season in August

Time Spent in Various Temperature Bands and the Growing Season in August in San Antonio1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JulSep100%Aug 16100%Aug 16100%Jul 3100%Jul 3warmhotcomfortable
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

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 San Antonio are very rapidly increasing during August, increasing by 950°F, from 6,113°F to 7,063°F, over the course of the month.

Growing Degree Days in August

Growing Degree Days in August in San Antonio1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031316,000°F6,000°F6,200°F6,200°F6,400°F6,400°F6,600°F6,600°F6,800°F6,800°F7,000°F7,000°F7,200°F7,200°FJulSepAug 16,113°FAug 16,113°FAug 317,063°FAug 317,063°FAug 116,430°FAug 116,430°FAug 216,746°FAug 216,746°F
The average growing degree days accumulated over the course of August, 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 Antonio is essentially constant during August, remaining within 0.2 kWh of 5.5 kWh throughout.

Average Daily Incident Shortwave Solar Energy in August

Average Daily Incident Shortwave Solar Energy in August in San Antonio1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWhJulSepAug 15.7 kWhAug 15.7 kWhAug 315.4 kWhAug 315.4 kWhAug 115.6 kWhAug 115.6 kWhAug 215.6 kWhAug 215.6 kWh
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 Antonio are 18.449 deg latitude, -66.303 deg longitude, and 23 ft elevation.

The topography within 2 miles of San Antonio contains only modest variations in elevation, with a maximum elevation change of 331 feet and an average elevation above sea level of 90 feet. Within 10 miles contains only modest variations in elevation (1,378 feet). Within 50 miles contains very significant variations in elevation (4,390 feet).

The area within 2 miles of San Antonio is covered by trees (33%), cropland (29%), grassland (20%), and shrubs (15%), within 10 miles by water (44%) and trees (23%), and within 50 miles by water (69%) and trees (16%).

Data Sources

This report illustrates the typical weather in San Antonio, 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 Antonio.

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

The stations contributing to this reconstruction are: Luis Muñoz Marín International Airport (62%, 31 kilometers, east); Mercedita Airport (25%, 56 kilometers, southwest); and Rafael Hernandez Airport (13%, 87 kilometers, west).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , 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 airports 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.

Disclaimer

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.