 The primary source of precipitation in Clearfield City is massive Pacific storms that move in from the Pacific Ocean along the jet stream from approximately October through May.Particularly cold storms have brought measurable snow as early as September and as late as May.After the Pacific train of storms has shut off and the jet stream has retreated far to the north during summer, the primary source of precipitation is afternoon thunderstorms generated by monsoon moisture moving up from the Gulf of California during mid-to-late summer.