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December Weather in San Antonio Texas, United States

Daily high temperatures decrease by 5°F, from 68°F to 63°F, rarely falling below 48°F or exceeding 79°F.

Daily low temperatures decrease by 5°F, from 49°F to 43°F, rarely falling below 31°F or exceeding 64°F.

For reference, on August 5, the hottest day of the year, temperatures in San Antonio typically range from 76°F to 96°F, while on January 6, the coldest day of the year, they range from 43°F to 63°F.

Average High and Low Temperature in December in San Antonio

Average High and Low Temperature in December in San AntonioDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313130°F30°F35°F35°F40°F40°F45°F45°F50°F50°F55°F55°F60°F60°F65°F65°F70°F70°F75°F75°F80°F80°F85°F85°FNovJanDec 168°FDec 168°F49°F49°FDec 3163°FDec 3163°F43°F43°FDec 1166°FDec 1166°F46°F46°FDec 2164°FDec 2164°F45°F45°F
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 December. 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 December in San Antonio

Average Hourly Temperature in December in San AntonioDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMNovJancoldcoldcoolcomfortablevery cold
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.

Ben Gardane, Tunisia (6,136 miles away); Ismailia, Egypt (7,183 miles); and Riāsi, India (8,105 miles) are the far-away foreign places with temperatures most similar to San Antonio (view comparison).

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The month of December in San Antonio experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 38% to 46%.

The clearest day of the month is December 2, with clear, mostly clear, or partly cloudy conditions 62% of the time.

For reference, on January 3, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 46%, while on June 10, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 73%.

Cloud Cover Categories in December in San Antonio

Cloud Cover Categories in December in San AntonioDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%NovJanDec 162%Dec 162%Dec 3154%Dec 3154%Dec 1158%Dec 1158%Dec 2155%Dec 2155%clearmostly clearpartly cloudymostly cloudyovercast
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.

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 December is essentially constant, remaining around 14% throughout.

For reference, the year's highest daily chance of a wet day is 31% on May 26, and its lowest chance is 13% on December 15.

Probability of Precipitation in December in San Antonio

Probability of Precipitation in December in San AntonioDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%2%2%4%4%6%6%8%8%10%10%12%12%14%14%16%16%18%18%20%20%22%22%NovJanDec 1513%Dec 1513%Dec 115%Dec 115%Dec 3113%Dec 3113%rainmixed
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 December in San Antonio is essentially constant, remaining about 1.6 inches throughout, and rarely exceeding 4.1 inches or falling below 0.1 inches.

Average Monthly Rainfall in December in San Antonio

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 snowfall.

Over the course of December in San Antonio, the length of the day is essentially constant. The shortest day of the month is December 20, with 10 hours, 16 minutes of daylight and the longest day is December 1, with 10 hours, 23 minutes of daylight.

Hours of Daylight and Twilight in December in San Antonio

Hours of Daylight and Twilight in December in San AntonioDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrNovJanDec 2110 hr, 16 minDec 2110 hr, 16 minnightnightdaydayDec 110 hr, 23 minDec 110 hr, 23 min
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 7:11 AM on December 1 and the latest sunrise is 17 minutes later at 7:28 AM on December 31.

The earliest sunset is 5:34 PM on December 1 and the latest sunset is 11 minutes later at 5:46 PM on December 31.

Daylight saving time is observed in San Antonio during 2024, but it neither starts nor ends during December, so the entire month is in daylight saving time.

For reference, on June 20, the longest day of the year, the Sun rises at 6:34 AM and sets 14 hours, 2 minutes later, at 8:36 PM, while on December 21, the shortest day of the year, it rises at 7:24 AM and sets 10 hours, 16 minutes later, at 5:40 PM.

Sunrise & Sunset with Twilight and Daylight Saving Time in December in San Antonio

Sunrise & Sunset with Twilight and Daylight Saving Time in December in San AntonioDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031312 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMNovJan7:11 AM7:11 AMDec 15:34 PMDec 15:34 PM7:28 AM7:28 AMDec 315:46 PMDec 315:46 PM7:18 AM7:18 AMDec 115:36 PMDec 115:36 PM7:24 AM7:24 AMDec 215:40 PMDec 215:40 PMSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of December. 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.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

Solar Elevation and Azimuth in December in San Antonio

Solar Elevation and Azimuth in December in San AntonioDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMNovJan001010202030304000101020203030
northeastsouthwest
Solar elevation and azimuth over the course of December 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for December 2024. 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 December in San Antonio

Moon Rise, Set & Phases in December in San AntonioDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMNovJanNov 17:48 AMNov 17:48 AMNov 153:29 PMNov 153:29 PMDec 112:22 AMDec 112:22 AMDec 153:02 AMDec 153:02 AMDec 304:28 PMDec 304:28 PMJan 134:28 PMJan 134:28 PMJan 296:37 AMJan 296:37 AM7:54 AM7:54 AM6:47 PM6:47 PM5:24 PM5:24 PM7:56 AM7:56 AM7:42 AM7:42 AM5:48 PM5:48 PM4:53 PM4:53 PM7:51 AM7:51 AM7:28 AM7:28 AM5:31 PM5:31 PM5:46 PM5:46 PM8:18 AM8:18 AM7:44 AM7:44 AM6:32 PM6:32 PM
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.
Dec 2024IlluminationMoonriseMoonsetMoonriseMeridian PassingDistance
1
0%7:42 AMESE5:48 PMWSW-12:45 PMS245,236 mi
2
3%8:41 AMESE6:41 PMWSW-1:41 PMS243,149 mi
3
7%9:36 AMESE7:41 PMWSW-2:39 PMS241,014 mi
4
13%10:26 AMESE8:45 PMWSW-3:36 PMS238,867 mi
5
22%11:10 AMESE9:50 PMWSW-4:30 PMS236,728 mi
6
32%11:49 AMESE10:54 PMWSW-5:22 PMS234,614 mi
7
43%12:23 PMESE11:58 PMW-6:10 PMS232,564 mi
8
50%12:56 PME--6:57 PMS230,652 mi
9
66%-1:01 AMW1:27 PME7:44 PMS228,996 mi
10
77%-2:06 AMW1:59 PME8:33 PMS227,750 mi
11
86%-3:12 AMWNW2:34 PMENE9:24 PMS227,090 mi
12
94%-4:20 AMWNW3:14 PMENE10:19 PMS227,174 mi
13
98%-5:32 AMWNW4:00 PMENE11:19 PMS228,109 mi
14
99%-6:43 AMWNW4:53 PMENE--
15
100%-7:51 AMWNW5:54 PMENE12:21 AMS229,911 mi
16
99%-8:51 AMWNW6:59 PMENE1:24 AMS232,480 mi
17
95%-9:43 AMWNW8:05 PMENE2:23 AMS235,612 mi
18
89%-10:26 AMWNW9:08 PMENE3:18 AMS239,031 mi
19
82%-11:02 AMWNW10:08 PMENE4:08 AMS242,439 mi
20
73%-11:32 AMWNW11:04 PME4:53 AMS245,556 mi
21
64%-12:00 PMW11:58 PME5:34 AMS248,144 mi
22
50%-12:26 PMW-6:14 AMS250,027 mi
23
44%12:51 AME12:52 PMW-6:52 AMS251,095 mi
24
35%1:43 AME1:18 PMWSW-7:31 AMS251,310 mi
25
26%2:37 AMESE1:47 PMWSW-8:12 AMS250,702 mi
26
18%3:33 AMESE2:19 PMWSW-8:56 AMS249,362 mi
27
11%4:31 AMESE2:56 PMWSW-9:43 AMS247,433 mi
28
5%5:30 AMESE3:41 PMWSW-10:35 AMS245,096 mi
29
2%6:30 AMESE4:32 PMWSW-11:31 AMS242,551 mi
30
0%7:28 AMESE5:31 PMWSW-12:30 PMS239,997 mi
31
1%8:21 AMESE6:35 PMWSW-1:28 PMS237,606 mi

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 decreasing during December, falling from 8% to 3% over the course of the month.

For reference, on June 30, the muggiest day of the year, there are muggy conditions 89% of the time, while on January 23, the least muggy day of the year, there are muggy conditions 2% of the time.

Humidity Comfort Levels in December in San Antonio

Humidity Comfort Levels in December in San AntonioDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%NovJanDec 18%Dec 18%Dec 313%Dec 313%Dec 115%Dec 115%Dec 215%Dec 215%muggymuggyhumidhumiddrydrycomfortablecomfortableoppressiveoppressive
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.

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 essentially constant during December, remaining within 0.1 miles per hour of 9.2 miles per hour throughout.

For reference, on April 1, the windiest day of the year, the daily average wind speed is 10.4 miles per hour, while on September 4, the calmest day of the year, the daily average wind speed is 7.9 miles per hour.

Average Wind Speed in December in San Antonio

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The wind direction in San Antonio during December is predominantly out of the south from December 1 to December 8 and the north from December 8 to December 31.

Wind Direction in December in San Antonio

Wind Direction in December in San AntonioSNDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%20%80%40%60%60%40%80%20%100%0%NovJansoutheastnorthwest
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).

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 San Antonio typically lasts for 9.8 months (299 days), from around February 15 to around December 9, rarely starting after March 11, or ending before November 17.

During December in San Antonio, the chance that a given day is within the growing season is very rapidly decreasing falling from 69% to 14% over the course of the month.

Time Spent in Various Temperature Bands and the Growing Season in December in San Antonio

Time Spent in Various Temperature Bands and the Growing Season in December in San AntonioDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%NovJan69%Dec 169%Dec 1Dec 3114%Dec 3114%Dec 1146%Dec 1146%Dec 2125%Dec 2125%90%Nov 1790%Nov 17very coldcoldcoolcomfortablewarmfreezing
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 increasing during December, increasing by 216°F, from 7,045°F to 7,261°F, over the course of the month.

Growing Degree Days in December in San Antonio

Growing Degree Days in December in San AntonioDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031316,800°F6,800°F6,900°F6,900°F7,000°F7,000°F7,100°F7,100°F7,200°F7,200°F7,300°F7,300°F7,400°F7,400°F7,500°F7,500°FNovJanDec 17,045°FDec 17,045°FDec 317,261°FDec 317,261°FDec 117,128°FDec 117,128°FDec 217,200°FDec 217,200°F
The average growing degree days accumulated over the course of December, with 25th to 75th and 10th to 90th percentile bands.

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 December, remaining within 0.1 kWh of 3.3 kWh throughout.

The lowest average daily incident shortwave solar energy during December is 3.2 kWh on December 18.

Average Daily Incident Shortwave Solar Energy in December in San Antonio

Average Daily Incident Shortwave Solar Energy in December in San AntonioDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310.0 kWh0.0 kWh0.5 kWh0.5 kWh1.0 kWh1.0 kWh1.5 kWh1.5 kWh2.0 kWh2.0 kWh2.5 kWh2.5 kWh3.0 kWh3.0 kWh3.5 kWh3.5 kWh4.0 kWh4.0 kWh4.5 kWh4.5 kWh5.0 kWh5.0 kWh5.5 kWh5.5 kWhNovJanDec 183.2 kWhDec 183.2 kWhDec 13.4 kWhDec 13.4 kWhDec 313.2 kWhDec 313.2 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.

For the purposes of this report, the geographical coordinates of San Antonio are 29.424 deg latitude, -98.494 deg longitude, and 636 ft elevation.

The topography within 2 miles of San Antonio contains only modest variations in elevation, with a maximum elevation change of 151 feet and an average elevation above sea level of 657 feet. Within 10 miles contains only modest variations in elevation (577 feet). Within 50 miles contains significant variations in elevation (1,831 feet).

The area within 2 miles of San Antonio is covered by artificial surfaces (100%), within 10 miles by artificial surfaces (65%) and shrubs (23%), and within 50 miles by shrubs (38%) and cropland (25%).

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:

To get a sense of how much these sources agree with each other, you can view a comparison of San Antonio and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data.

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 © OpenStreetMap contributors.

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.

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