New Braunfels has a humid subtropical climate that lends to hot summers and usually mild winters, though it is not impossible to see ice or even snow here, the average annual snowfall is only 0.24 inches. Average daily temperatures range from anywhere from 83 °F (27.8 °C) in the summer to 49 °F (9.4 °C) in the winter. The average annual temperature is 67.3 °F (19.6 °C). The record high for New Braunfels was 112 °F (44 °C) in September 2000, and the record low for the city is tied at 2 °F (-17 °C) in 1949 and 1989. The Comal River in the middle of the town is always at 70-72 degrees Fahrenheit due to its spring source. The River is also the shortest in the world, measuring in at only two miles long. The most precipitous months are May, June, and October. The area receives about 35 inches of precipitation every year, but there are usually no more than 5 precipitous days a month here. Annual average humidity in New Braunfels is 78.60 percent, which is only a point above the national average and two points above the state average. The average annual wind speed here is 15.66 mph, which is in line with state and national averages.
New Braunfels does have a tornado risk at 154.90 on the tornado index – above the national average but well below the 208.58 rating for the whole state of Texas. One of the worst tornados to hit the region was on May 27th, 1997. An F4 Tornado started on the shores of nearby Lake Travis and traveled 5.6 miles. The tornado would destroy numerous subdivisions, businesses, and even a steel tower from a major power line, totaling $15 million in damages. Five were injured from the storm, and one man died. The only other known F4 tornado to strike down was in April of 1953. The twister only lasted a mile, but was 1760 yards wide and injured 15 while killing two. The costliest storm ever in the area happened on August 10th 1980 and totaled $250 million in damages.
New Braunfels has absolutely zero risks of a nearby volcanic eruption, and virtually no risk of an earthquake, only registering a 0.01 on the scale. There have been 1,017 recorded hail storms, 833 floods, 651 thunderstorm winds, 94 instances of drought, 17 winter storms, four heavy snow events, three tropical storms, and three wildfires. The air quality rating for New Braunfels is about 36, which is better than both the state and national average of about 38. Both levels are considered good and safe. Lead, Carbon Monoxide, Sulfur Dioxide, Nitrogen Dioxide, Ozone, and total suspended particulates have all been decreasing and have been lower than state and national averages.