Excessive Rainfall and Tropical Storm in the South; Severe Thunderstorms in the Midwest

Excessive rainfall may produce considerable, potentially life-threatening, flooding across the lower Mississippi River Valley and central Great Lakes region through tonight. Tropical Storm Arthur will move northeastward along the Texas coast today and then move inland over southwestern Louisiana by tonight. An outbreak of severe thunderstorms is expected across portions of Illinois and Indiana. Read More >

Hazardous Weather Conditions

Extreme Heat Warning in effect from June 18, 12:00 PM CDT until June 18, 08:00 PM CDT

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Fair

90°F

32°C

Humidity	62%
Wind Speed	NE 5 mph
Barometer	29.65 in (1003.1 mb)
Dewpoint	75°F (24°C)
Visibility	10.00 mi
Heat Index	101°F (38°C)
Last update	17 Jun 4:56 pm CDT

More Information:

Local Forecast Office More Local Wx 3 Day History Hourly Weather Forecast

Extended Forecast for

3 Miles WSW San Marcos TX

Extreme Heat Warning June 18, 12:00pm until June 18, 08:00pm

Click here for hazard details and duration

Extreme Heat Warning

Tonight
Low: 77 °F
Mostly Clear
Thursday
High: 95 °F
Becoming
Sunny
Thursday Night
Low: 79 °F
Mostly Cloudy
Juneteenth
High: 92 °F
Partly Sunny
Friday Night
Low: 78 °F
Chance
T-storms then
Chance
Showers
Saturday
High: 91 °F
Slight Chance
T-storms then
Chance
T-storms
Saturday Night
Low: 77 °F
Slight Chance
T-storms
Sunday
High: 94 °F
Partly Sunny
Sunday Night
Low: 77 °F
Mostly Clear

Detailed Forecast

Tonight

Mostly clear, with a low around 77. South wind 5 to 10 mph.

Thursday

Mostly cloudy through mid morning, then gradual clearing, with a high near 95. Heat index values as high as 110. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

Thursday Night

Mostly cloudy, with a low around 79. South southeast wind 5 to 15 mph, with gusts as high as 20 mph.

Juneteenth

Partly sunny, with a high near 92. Heat index values as high as 105. Southeast wind 5 to 10 mph, with gusts as high as 20 mph.

Friday Night

A chance of showers and thunderstorms before 1am, then a slight chance of showers between 1am and 4am, then a slight chance of showers and thunderstorms after 4am. Mostly cloudy, with a low around 78. South southeast wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 30%.

Saturday

A 50 percent chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 91. South wind 5 to 10 mph, with gusts as high as 20 mph.

Saturday Night

A slight chance of showers and thunderstorms. Mostly cloudy, with a low around 77. South southeast wind around 10 mph. Chance of precipitation is 20%.

Sunday

Partly sunny, with a high near 94. South wind 10 to 15 mph, with gusts as high as 25 mph.

Sunday Night

Mostly clear, with a low around 77. South southeast wind around 15 mph, with gusts as high as 25 mph.

Monday

Mostly sunny, with a high near 95.

Monday Night

Mostly clear, with a low around 77.

Tuesday

Partly sunny, with a high near 94.

Tuesday Night

Partly cloudy, with a low around 76.