Chi Epsilon Pi (ΧΕΠ) (Also known as XEP) is an American honor society for outstanding students in the field of meteorology/atmospheric sciences.

Chi Epsilon Pi was founded at Department of Atmospheric and Oceanic Sciences of University of California, Los Angeles in 1951.

[3] Its national office is housed at 405 Hilgard Avenue, 7127 Math Sciences Building in Los Angeles, California.

[5] The name Chi Epsilon Pi {ΧΕΠ} was selected to represent ΧΕΙΜΩΝΑΣ ΕΗΙΟΝΤΑΣ ΠΡΟΛΕΓΟΜΕΝ or "Past Events Cast Their Shadows Before Them.

[2] Active members include students who have completed ten credits toward a meteorology major with a 3.0 cumulative GPA.