San Marcos, TX 78666 Weather

: New SHORT TERM, LONG TERM:

Key messages

Updated at 130 PM CDT Fri Oct 30 2026

- Rain chances continue through Saturday afternoon, mainly north of US Highway 90, with a drying trend for the evening Halloween festivities.

- Warmer afternoons with rain-free conditions Sunday/Monday in advance of a cold front Tuesday which could bring a line of showers and storms to most areas.

- A drier airmass arrives mid to late next week behind the front with cooler mornings and mild but pleasant afternoons.

Short term

(Tonight through Saturday night) Issued at 130 PM CDT Fri Oct 30 2026

The latest SPC Mesoanalysis shows broad southwesterly flow aloft at the 500mb level over the western CONUS, along with a decent shortwave swinging through South Central Texas. Showers and the occasional rumble of thunder will continue to spread east through the afternoon hours. Flooding rains are still possible, but the primary concern for flash flooding has ended. Beneficial stratiform rain will continue through the day with some redevelopment possible this afternoon, primarily along and east of US-281. At this time, severe weather is not expected, however, the SPC mesoanalysis does show a subtle mesolow sliding east with this shower activity, as well as 150-200 m2/s2 of SRH at in the 0-1 km layer, so a quick spin up or funnel isn't out of the realm of possibility. HOWEVER, instability is nonexistent, so concerns are quite low.

For tonight, expect spotty rain showers, but concerns for heavy rain that could lead to flooding will end. Temperatures probably won't dip much lower than afternoon highs as cloud cover and drizzle linger.

On Halloween day, temperatures should warm back closer to the mid 70s and as warm as the lower 80s. Some lingering showers or sprinkles are possible in the morning hours but the afternoon should be dry along with a few peaks of sunshine. Models and hi-res guidance has trended drier for Halloween, which is a good thing for Trick or Treaters.

Long term

(Sunday through next Friday) Issued at 130 PM CDT Fri Oct 30 2026

Sunday and Monday will be drier with warmer afternoons and more partly to mostly cloudy skies. Highs should climb into the upper 70s to middle 80s both days with warmer temperatures south of Highway 90/I-10. Weak shortwave ridging will be the reason for warmer and drier weather both Sunday and Monday before a powerful trough digs over the southern Rockies Monday. This will send a stronger cold front in our direction on Election Day, with the potential for thunderstorms, some strong to severe with large hail and damaging winds possible. This would be more of a line of storms rather than the large, stratiform type rain we've had the last 24-36 hours. Beyond Tuesday, the pattern turns drier and cooler. Each morning will start in the 40s and 50s followed by afternoons in the 70s.

Aviation

(18Z TAFS) Issued at 102 PM CDT Fri Oct 30 2026

Widespread light to moderate rainfall will continue to lift northward through the afternoon and evening hours. Based on current radar and observational trends, we will keep prevailing RA and BR intact through early evening along with low end MVFR and IFR cigs for the I-35 sites. The rain should then taper off overnight, but IFR cigs and BR will continue. Some slow improvement back to low end MVFR is anticipated late tomorrow morning for the I-35 sites. Out west at DRT, the rain has ended for the forecast period, but cigs should remain IFR through the afternoon. We did opt to add a TEMPO group for some brief improvement to MVFR late this afternoon based on satellite trends. Otherwise, IFR should quickly develop after 02Z with moist boundary layer conditions.

Preliminary point temps/pops

Austin Camp Mabry 62 78 65 84 / 50 20 10 0 Austin Bergstrom Intl Airport 62 79 64 85 / 50 20 10 0 New Braunfels Muni Airport 61 79 64 84 / 50 20 0 0 Burnet Muni Airport 60 74 63 81 / 40 20 10 0 Del Rio Intl Airport 64 76 67 81 / 30 10 10 10 Georgetown Muni Airport 60 77 63 84 / 50 20 10 0 Hondo Muni Airport 62 78 65 82 / 40 10 10 0 San Marcos Muni Airport 61 79 64 85 / 50 20 10 0 La Grange - Fayette Regional 64 81 66 86 / 50 20 10 0 San Antonio Intl Airport 63 78 66 82 / 40 10 0 0 Stinson Muni Airport 65 79 67 83 / 40 10 0 0

Watches, warnings and advisories

None.