Below is a list of Dewey County OK zip codes. For your research we have also included Dewey County Area Code, Time Zone, UTC and the local County FIPS Code. Each Dewey County Oklahoma zip code has a center Longitude / Latitude point (the Dewey County center is -99.017601013184 / 35.979999542236). For your convenience we have also indicated if that zip code in Dewey County observes Daylight Savings time.