San Antonio is far enough north of the equator where bitter-cold temperatures and snowfall are not out of the realm of possibility. But we also sit close enough to the Gulf of Mexico that significant winter weather doesn’t happen very often. So, to see San Antonio’s all-time record low temperature is shocking, even to a meteorologist. Zero. Yes, San Antonio dropped all the way down to zero degrees on the morning of January 31, 1949. As you would expect, it took a rare combination of events to get the mercury that low.