September in Santa Cruz is the sunniest and the warmest month of the year. In September, the weather in Santa Cruz is typically warm. Average daily high temperature in September is about 17 degrees above zero. On average, Santa Cruz has 22 sunny, 7 partly cloudy, and 1 rainy day in September. The rains are usually light. September as well as July, August, and October is considered the most comfortable time to visit Santa Cruz.