Kristen’s Classroom: Austin’s 100-degree days AUSTIN (KXAN) – Triple digits are to be expected in Austin during the summertime. But as we're now a week into July with no 100-degree days yet, some may wonder if this is normal. Let's dive into the numbers. First 100-degree day On average, our first triple-digit day in Austin is July 4. When we look back at recent years, though, our first 100-degree day has come much sooner. But records show we've had our first 100-degree day come much later as well.