San Antonio is hot and humid. If you are planning to attend UIW, you must bring all your summer clothes and a lot of sunscreen. Of course, it is also a must to bring some winter fashions, as it does get chilly from late-November through mid-February. Bring a versatile wardrobe so that you are prepared for any kind of weather.
Since San Antonio is just a few hours away from great beaches, such as South Padre Island and Corpus Christi, you'll probably get more use out of those summer clothes than the winter ones. During the months of summer heat, the buildings at UIW are equipped with air conditioning, so what ever the weather may be, you can be assured that you will feel comfortable at UIW.