Below is a list of Thornton IA zip codes. For your research we have also included Thornton Area Code, Time Zone, UTC and the local Cerro Gordo County FIPS Code. Each Thornton Iowa zip code has a center Longitude / Latitude point (the Thornton center is -93.387100219727 / 42.944499969482). For your convenience we have also indicated if that zip code in Thornton observes Daylight Savings time.