SAN MARCOS, TX 78666 Weather Forecast & Current Conditions
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  78666 WEATHER WARNINGS (SEVERE T-STORM & TORNADO)
 CURRENT WEATHER

SAN MARCOS, TX
Current Weather
7:56 AM CDT APR 9, 2026
Overcast
Mist
66°F
Feels Like: 66°F
Dewpoint: 64°F
Rel. Hum.: 93%
Visibility: 10 miles
Wind: SE at 7 mph
Pressure: 30.13 inches
Last 72 hours

Local Area Snow Depth

Texas Current Weather

Texas MOS Forecast Weather


Weather Map

(Automated weather data from NWS/FAA)
  78666 WEATHER FORECAST
10-Day model forecast maps
2025 Hurricanes

SAN MARCOS, TX 78666
Weather Forecast

 Snowfall Forecast pages
Snow Depth pages
TODAY
Mostly cloudy. A chance of showers and thunderstorms this afternoon. Highs around 80. Southeast winds 5 to 10 mph. Chance of rain 50 percent.
TONIGHT
Cloudy with a chance of showers. A chance of thunderstorms, mainly in the evening. Patchy fog after midnight. Lows in the mid 60s. Southeast winds 5 to 10 mph. Chance of rain 50 percent.
FRIDAY
Mostly cloudy. Patchy fog in the morning. A chance of showers with a slight chance of thunderstorms in the morning, then showers likely with a chance of thunderstorms in the afternoon. Highs in the upper 70s. Southeast winds 5 to 10 mph. Chance of rain 60 percent.
FRIDAY NIGHT
Mostly cloudy. A slight chance of showers and thunderstorms in the evening. Lows in the mid 60s. Southeast winds 5 to 10 mph.
SATURDAY
Cloudy. A slight chance of showers and thunderstorms in the morning, then a chance of showers and thunderstorms in the afternoon. Highs around 80. Southeast winds 10 to 15 mph with gusts up to 25 mph. Chance of rain 50 percent.
SATURDAY NIGHT
Cloudy with a slight chance of showers and thunderstorms. Lows in the upper 60s.
SUNDAY
Cloudy. A slight chance of showers and thunderstorms in the morning, then a chance of showers and thunderstorms in the afternoon. Highs around 80. Chance of rain 50 percent.
SUNDAY NIGHT
Cloudy. A chance of showers and thunderstorms in the evening. Lows in the upper 60s. Chance of rain 30 percent.
MONDAY
Mostly cloudy. Highs in the lower 80s.
MONDAY NIGHT
Cloudy. Lows in the upper 60s.
TUESDAY
Cloudy. A chance of showers with a slight chance of thunderstorms in the afternoon. Highs in the lower 80s. Chance of rain 30 percent.
TUESDAY NIGHT
Cloudy with a slight chance of showers and thunderstorms. Lows in the mid 60s.
WEDNESDAY
Cloudy with a chance of thunderstorms. A chance of showers. Highs around 80. Chance of rain 50 percent.

  78666 WEATHER SATELLITE LOOPS
Visible Weather Satellite
SAN MARCOS, TX 78666
Infrared Weather Satellite
SAN MARCOS, TX 78666
  78666 WEATHER RADAR LOOP
NEXRAD Weather Radar
SAN MARCOS, TX 78666
 MOS COMPUTER WEATHER FORECAST

SAN MARCOS, TX 3 hourly weather forecast
weather forecast created  8:00 PM EDT  4/ 8/2026
Thursday
9 APR 2026		 SAN MARCOS, TX 78666 weather forecast Day 1, 0 hours 1 AM 65° 65° Partly Cloudy 2%

 0% Thunder
( 1% severe)		 SSE   6 81% 59°
Low 62° SAN MARCOS, TX 78666 weather forecast Day 1, 3 hours 4 AM 63° 64° Mostly Cloudy SE   3 90% 60°
High 82° SAN MARCOS, TX 78666 weather forecast Day 1, 6 hours 7 AM 63° 64° Mostly Cloudy 17%
RAIN
<.01 in		 0% Thunder
( 12% severe)		 ESE   3 93% 61°

Mostly Cloudy

Chance of Rain

 SAN MARCOS, TX 78666 weather forecast Day 1, 9 hours 10 AM 69° 69° Mostly Cloudy ESE   7 84% 64°
SAN MARCOS, TX 78666 weather forecast Day 1, 12 hours 1 PM 77° 79° Mostly Cloudy 41%
RAIN
***		 0% Thunder
( 33% severe)		 ESE   9 62% 63°
SAN MARCOS, TX 78666 weather forecast Day 1, 15 hours 4 PM 79° 80° Mostly Cloudy ESE   12 56% 62°
SAN MARCOS, TX 78666 weather forecast Day 1, 18 hours 7 PM 76° 78° Mostly Cloudy 37%
RAIN
.5–1 in		 0% Thunder
( 27% severe)		 ESE   12 62% 62°
SAN MARCOS, TX 78666 weather forecast Day 1, 21 hours 10 PM 69° 69° Mostly Cloudy SE   8 81% 63°
Friday
10 APR 2026		 SAN MARCOS, TX 78666 weather forecast Day 2, 0 hours 1 AM 67° 67° Mostly Cloudy 22%
RAIN
.01–.1 in		 0% Thunder
( 18% severe)		 SSE   6 87% 63°
Low 63° SAN MARCOS, TX 78666 weather forecast Day 2, 3 hours 4 AM 66° 66° Mostly Cloudy SE   5 90% 63°
High 81° SAN MARCOS, TX 78666 weather forecast Day 2, 6 hours 7 AM 65° 65° Mostly Cloudy 23%
RAIN
.01–.1 in		 0% Thunder
( 21% severe)		 ESE   5 97% 64°

Mostly Cloudy

Rain Likely

 SAN MARCOS, TX 78666 weather forecast Day 2, 9 hours 10 AM 70° 70° Mostly Cloudy ESE   7 87% 66°
SAN MARCOS, TX 78666 weather forecast Day 2, 12 hours 1 PM 77° 79° Mostly Cloudy 52%
RAIN
***		 0% Thunder
( 36% severe)		 SE   10 67% 65°
SAN MARCOS, TX 78666 weather forecast Day 2, 15 hours 4 PM 78° 80° Mostly Cloudy SE   12 62% 64°
SAN MARCOS, TX 78666 weather forecast Day 2, 18 hours 7 PM 76° 78° Mostly Cloudy 14%
RAIN
.01–.1 in		 0% Thunder
( 13% severe)		 ESE   12 64% 63°
SAN MARCOS, TX 78666 weather forecast Day 2, 21 hours 10 PM 70° 70° Mostly Cloudy SE   8 81% 64°

SAN MARCOS, TX extended weather forecast
Saturday
11 APR 2026		 Sunday
12 APR 2026		 Monday
13 APR 2026		 Tuesday
14 APR 2026		 Wednesday
15 APR 2026
Low 65° Low 70° Low 66° Low 68° Low 66°
High 82° High 82° High 84° High 82° High 84°
SAN MARCOS, TX 78666 weather forecast Day 3 SAN MARCOS, TX 78666 weather forecast Day 4 SAN MARCOS, TX 78666 weather forecast Day 5 SAN MARCOS, TX 78666 weather forecast Day 6 SAN MARCOS, TX 78666 weather forecast Day 7
Overcast
36% Rain		 Overcast
46% Rain		 Overcast
37% Rain		 Overcast
31% Rain		 Overcast
34% Rain
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