San Antonio, Texas, Average Temperature, 18-Month Period Ending in April Degrees Fahrenheit 1901-1913 -99 189704 66.1 0.7 189804 66.2 0.8 189904 64.6 -0.8 190004 64.3 -1.1 190104 65.4 0.0 190204 65.7 0.3 190304 65.2 -0.2 190404 64.2 -1.2 190504 64.7 -0.7 190604 64.0 -1.4 190704 65.8 0.4 190804 66.9 1.5 190904 66.1 0.7 191004 66.6 1.2 191104 66.8 1.4 191204 65.7 0.3 191304 63.5 -1.9