Below is a list of Westmont IL zip codes. For your research we have also included Westmont Area Code, Time Zone, UTC and the local Dupage County FIPS Code. Each Westmont Illinois zip code has a center Longitude / Latitude point (the Westmont center is -87.9727 / 41.795). For your convenience we have also indicated if that zip code in Westmont observes Daylight Savings time. For more information on Westmont Illinois you will find helpful business links and searches.