National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Fair

77°F

25°C

Humidity 85%
Wind Speed NW 12 mph
Barometer 30.01 in (1015.2 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 28 Aug 12:56 am CDT
Extended Forecast for

3 Miles NNW San Marcos Municipal Airport TX

  • Overnight

    Overnight: Mostly cloudy, with a low around 76. Calm wind.

    Low: 76 °F

    Mostly Cloudy

  • Friday

    Friday: A slight chance of showers between 1pm and 4pm, then a slight chance of showers and thunderstorms after 4pm. Mostly sunny, with a high near 98. Heat index values as high as 105. Calm wind becoming east around 5 mph in the afternoon. Chance of precipitation is 20%.

    High: 98 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Friday Night

    Friday Night: A slight chance of showers and thunderstorms before 7pm, then a slight chance of showers between 7pm and 10pm. Mostly clear, with a low around 75. East wind around 5 mph becoming calm in the evening. Chance of precipitation is 20%.

    Low: 75 °F

    Slight Chance
    T-storms then
    Mostly Clear

  • Saturday

    Saturday: Sunny, with a high near 98. Heat index values as high as 104. Calm wind becoming southeast around 5 mph in the afternoon.

    High: 98 °F

    Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 74. Southeast wind around 5 mph becoming south southwest after midnight.

    Low: 74 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 98. Calm wind becoming south southeast around 5 mph in the morning.

    High: 98 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 74. Southeast wind 5 to 10 mph.

    Low: 74 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 98. South wind around 5 mph.

    High: 98 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 75. Southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 75 °F

    Mostly Clear

Detailed Forecast

Overnight
Mostly cloudy, with a low around 76. Calm wind.
Friday
A slight chance of showers between 1pm and 4pm, then a slight chance of showers and thunderstorms after 4pm. Mostly sunny, with a high near 98. Heat index values as high as 105. Calm wind becoming east around 5 mph in the afternoon. Chance of precipitation is 20%.
Friday Night
A slight chance of showers and thunderstorms before 7pm, then a slight chance of showers between 7pm and 10pm. Mostly clear, with a low around 75. East wind around 5 mph becoming calm in the evening. Chance of precipitation is 20%.
Saturday
Sunny, with a high near 98. Heat index values as high as 104. Calm wind becoming southeast around 5 mph in the afternoon.
Saturday Night
Mostly clear, with a low around 74. Southeast wind around 5 mph becoming south southwest after midnight.
Sunday
Sunny, with a high near 98. Calm wind becoming south southeast around 5 mph in the morning.
Sunday Night
Mostly clear, with a low around 74. Southeast wind 5 to 10 mph.
Monday
Sunny, with a high near 98. South wind around 5 mph.
Monday Night
Mostly clear, with a low around 75. Southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Tuesday
Mostly sunny, with a high near 98.
Tuesday Night
Mostly clear, with a low around 75.
Wednesday
Mostly sunny, with a high near 98.
Wednesday Night
Mostly clear, with a low around 75.
Thursday
Mostly sunny and hot, with a high near 99.
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ABOUT THIS FORECAST

 
Point Forecast:
3 Miles NNW San Marcos Municipal Airport TX
 29.95°N 97.89°W (Elev. 646 ft)
Last Update:
1:28 am CDT Aug 28, 2026
Forecast Valid:
1am CDT Aug 28, 2026-6pm CDT Sep 3, 2026
 
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Additional Resources

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High Temperature

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Chance of Precipitation