Below is a list of Grinnell IA zip codes. For your research we have also included Grinnell Area Code, Time Zone, UTC and the local Poweshiek County FIPS Code. Each Grinnell Iowa zip code has a center Longitude / Latitude point (the Grinnell center is -92.765 / 41.7673). For your convenience we have also indicated if that zip code in Grinnell observes Daylight Savings time. For more information on Grinnell Iowa you will find helpful business links and searches.