Q.Climate Zones
How can one determine their “zone” when radical swings in temps have become the norm? Once again San Antonio has suffered a hard freeze. Before replanting What zone should they be using?

Certified GKH Gardening Expert
San Antonio is in USDA hardiness zone 8, with average minimum winter temperatures of 10 to 20 degrees F. So hard freezes are possible. If you are buying plants rated for zone 8, they should be OK. If your area has experienced temperatures below 10 degrees F., I would up the zone on new plant purchases to 7 to be on the safe side.
https://aggie-horticulture.tamu.edu/plantanswers/fallgarden/zones.html