We do not have enough data on this route to provide a reliable graph showing how many days before departure it is the best to book.
However, usually the closer it is to the departure, the more expensive the tickets are.
The most popular airlines on the route Chicago O'Hare - Salt Lake City Intl Airport: Delta Airlines (DL), American Airlines (AA), United Airlines (UA).
Direct flights last about 3h 26min.
Direct flights available 3 days a week - Wednesday, Thursday, Saturday.
Direct flights: Delta Airlines (DL), United Airlines (UA), American Airlines (AA).
Chicago (IL) Salt Lake City (UT)