SAN MARCOS, TX 78666 Weather Forecast & Current Conditions

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SAN MARCOS, TX
Current Weather

9:56 PM CDT AUG 3, 2026
Clear
88°F
Feels Like: 95°F
Dewpoint: 72°F
Rel. Hum.: 59%
Visibility: 10 miles
Wind: SSE at 16 mph
Pressure: 29.87 inches
Last 72 hours

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SAN MARCOS, TX 78666
Weather Forecast

Snowfall Forecast pages
Snow Depth pages
TONIGHT
Clear. Lows in the mid 70s. South winds 5 to 10 mph with gusts up to 20 mph.
TUESDAY
Mostly sunny. Highs in the upper 90s. South winds 5 to 10 mph. Highest heat index readings up to 105.
TUESDAY NIGHT
Clear in the evening, then becoming partly cloudy. Lows in the mid 70s. South winds 5 to 10 mph with gusts up to 20 mph.
WEDNESDAY
Partly cloudy in the morning, then clearing. Highs in the upper 90s. South winds 5 to 10 mph with gusts up to 20 mph. Highest heat index readings up to 106.
WEDNESDAY NIGHT
Clear in the evening, then becoming partly cloudy. Lows in the mid 70s. South winds 5 to 10 mph with gusts up to 20 mph.
THURSDAY AND THURSDAY NIGHT
Mostly clear. Highs in the mid 90s. Lows in the mid 70s. Highest heat index readings up to 105.
FRIDAY AND FRIDAY NIGHT
Partly cloudy with a slight chance of showers. Highs in the mid 90s. Lows in the mid 70s.
SATURDAY
Partly cloudy in the morning, then clearing. Highs in the mid 90s.
SATURDAY NIGHT
Mostly clear. Lows in the mid 70s.
SUNDAY THROUGH MONDAY
Partly cloudy. Highs in the mid 90s. Lows in the mid 70s.

Visible Weather Satellite
SAN MARCOS, TX 78666
Infrared Weather Satellite
SAN MARCOS, TX 78666
NEXRAD Weather Radar
SAN MARCOS, TX 78666

SAN MARCOS, TX 3 hourly weather forecast

weather forecast created  8:00 AM EDT  8/ 3/2026
Monday
3 AUG 2026
SAN MARCOS, TX 78666 weather forecast Day 1, 12 hours 1 PM 95° 101° Clear 0%

0% Thunder
( 9% severe)
S   6 43% 69°
High 100° SAN MARCOS, TX 78666 weather forecast Day 1, 15 hours 4 PM 99° 104° Clear S   6 36% 67°
Clear



SAN MARCOS, TX 78666 weather forecast Day 1, 18 hours 7 PM 97° 100° Clear 0%

0% Thunder
( 2% severe)
SSE   9 35% 65°
SAN MARCOS, TX 78666 weather forecast Day 1, 21 hours 10 PM 85° 90° Clear SSE   12 61% 70°
Tuesday
4 AUG 2026
SAN MARCOS, TX 78666 weather forecast Day 2, 0 hours 1 AM 80° 84° Clear 0%

0% Thunder
( 1% severe)
S   10 79% 73°
Low 76° SAN MARCOS, TX 78666 weather forecast Day 2, 3 hours 4 AM 77° 78° Partly Cloudy S   8 90% 74°
High 99° SAN MARCOS, TX 78666 weather forecast Day 2, 6 hours 7 AM 76° 75° Partly Cloudy 0%

0% Thunder
( 1% severe)
S   6 97% 75°

Partly Cloudy



SAN MARCOS, TX 78666 weather forecast Day 2, 9 hours 10 AM 84° 91° Partly Cloudy S   9 72% 74°
SAN MARCOS, TX 78666 weather forecast Day 2, 12 hours 1 PM 94° 102° Clear 0%

0% Thunder
( 7% severe)
S   10 49% 72°
SAN MARCOS, TX 78666 weather forecast Day 2, 15 hours 4 PM 98° 104° Clear S   12 39% 69°
SAN MARCOS, TX 78666 weather forecast Day 2, 18 hours 7 PM 95° 102° Clear 0%

0% Thunder
( 2% severe)
SSE   13 45% 70°
SAN MARCOS, TX 78666 weather forecast Day 2, 21 hours 10 PM 85° 91° Clear SSE   13 65% 72°
Wednesday
5 AUG 2026
SAN MARCOS, TX 78666 weather forecast Day 3, 0 hours 1 AM 80° 85° Clear 0%

0% Thunder
( 2% severe)
S   10 85% 75°
Low 76° SAN MARCOS, TX 78666 weather forecast Day 3, 3 hours 4 AM 77° 78° Mostly Cloudy S   8 97% 76°
High 99° SAN MARCOS, TX 78666 weather forecast Day 3, 6 hours 7 AM 76° 75° Mostly Cloudy 0%

0% Thunder
( 2% severe)
S   7 100% 76°

Decreasing Clouds



SAN MARCOS, TX 78666 weather forecast Day 3, 9 hours 10 AM 84° 91° Partly Cloudy S   9 72% 74°
SAN MARCOS, TX 78666 weather forecast Day 3, 15 hours 1 PM 93° 101° Clear 1%

0% Thunder
( 9% severe)
S   10 51% 72°
SAN MARCOS, TX 78666 weather forecast Day 3, 18 hours 4 PM 98° 104° Clear S   10 39% 69°
SAN MARCOS, TX 78666 weather forecast Day 3, 21 hours 7 PM 95° 102° Partly Cloudy     SSE   12 45% 70°

SAN MARCOS, TX extended weather forecast

Thursday
6 AUG 2026
Friday
7 AUG 2026
Saturday
8 AUG 2026
Sunday
9 AUG 2026
Monday
10 AUG 2026
Low 76° Low 76° Low 74° Low 74° Low 75°
High 100° High 92° High 97° High 98° High 99°
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 <!--SEARCHED_TOWN_NAME--> weather forecast Day 8
Partly Cloudy
12% Rain
Partly Cloudy
44% Rain
Partly Cloudy
26% Rain
Mostly Cloudy
18% Rain
Partly Cloudy
19% Rain
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