San Antonio, TX 78217 Weather

Key Messages

Updated at 549 AM CDT Wed Oct 21 2026

- Warm and rain-free conditions to persist into the weekend

- Modest Rain chances (15-35%) to return early next week

Short Term

(Today through Thursday) Issued at 129 AM CDT Wed Oct 21 2026

The mid-level ridge axis across northern Mexico will elongate northward through the short term period, setting up into an Omega Block pattern across the CONUS. Locally, this yields to benign weather with modest east-northeasterly to easterly winds under a mostly clear to partly cloudy sky. The daytime highs trend in the low to mid 80s for most while the morning lows this morning stay seasonable in the low to mid 50s, but trend milder for Thursday morning from the mid 50s to the mid 60s. Late Wednesday into Thursday does see a slug of moisture advance across South Texas, which perhaps has enough moisture reaching far enough north for a light sprinkle or virga with any thicker mid-level clouds within mostly the Rio Grande Plains. Elsewhere, rain is not expected through the short term.

Long Term

(Thursday night through Tuesday) Issued at 129 AM CDT Wed Oct 21 2026

The mid-level ridging stays in place through the end of the work week, which will keep the region warm and rain free. Changes then start to appear into and through the weekend as the flow aloft turns more southwesterly as the mid-level ridging nudges to the east and troughing slowly progresses across the Southwestern CONUS. Humidity also gradually increases from Friday through the weekend with the low-level and surface flow returning to and increasing from out of the southeast, helping to draw in the moisture off the Gulf. For the vast majority of the weekend, this would mainly just yield to more cloud cover, especially nocturnally into each morning. Any Rain chances (15-35%) are looking to hold off until early next week, with the potential for a front dropping southward into the region once the trough in the Desert Southwest starts to eject northeastward into the Texas and Oklahoma panhandle region. The deterministic medium range guidance remains a bit more bullish on this front than the ensembles means. This is due to a cluster of several ensembles that indicate the upper level pattern may not be conducive enough for the full push of a front across the region. The NBM guidance does indicate a northerly wind shift into early Tuesday behind the front but only marginal cooling in the wake of the boundary at this time. This is quite a bit of a weaker signal in comparison to the front last week. We'll continue to monitor, as this could change with these early season fronts.

Aviation

(12Z TAFS) Issued at 549 AM CDT Wed Oct 21 2026

No significant changes were made to the aviation forecasts with the 12Z update. VFR conditions are still expected through the period with mainly east winds along I-35 and southeast winds at DRT. A deck of low clouds may briefly move toward SAT/SSF late this evening into Thursday morning. Confidence in clouds reaching MVFR is low and we will not mention in this forecast update.