Below is a list of Westchester IL zip codes. For your research we have also included Westchester Area Code, Time Zone, UTC and the local Cook County FIPS Code. Each Westchester Illinois zip code has a center Longitude / Latitude point (the Westchester center is -87.886596679688 / 41.848499298096). For your convenience we have also indicated if that zip code in Westchester observes Daylight Savings time.