Gilbert, Arizona, gets 9 inches of rain per year. The US average is 39. Snowfall is 0 inches. The average US city gets 26 inches of snow per year. The number of days with any measurable precipitation is 20. On average, there are 296 sunny days per year in Gilbert, Arizona. The July high is around 105 degrees. The January low is 41. Sperling's comfort index for Gilbert is a 76 out of 100, where a higher score indicates a more comfortable year-around climate. The US average for the comfort index is 54.