Francis E. Warren Air Force Base Cheyenne, WY (FEW / KFEW)
South Big Horn County Airport Greybull, WY (GEY / KGEY)
Bozeman Yellowstone International Airport Bozeman, MT (BZN / KBZN)
Great Falls International Airport Great Falls, MT (GTF / KGTF)
Polson Airport Polson, MT (XXT)
Note that states may span multiple time zones, so it's often better to search for a particular city to find the local time zone.
Travelmath provides a database of time zones all over the world. You can use this data to check the local time, or verify the time difference when you cross time zones during a trip. Daylight savings is automatically adjusted based on the local time zone. The tz database or zoneinfo database uses the closest city, rather than the more common Eastern, Central, Mountain or Pacific time zones in the United States. Countries often change their daylight saving rules, so please help us stay current by letting us know if you find any pages that need updates.