The summer solstice begins on Tuesday, June 20 and Wednesday, June 21 (depending on your time zone.) For time zones further west, the solstice falls on Tuesday. The solstice will begin June 21 at 12:24 a.m. EDT and will continue west to Tuesday, June 20, 11:24 p.m. CDT, 10:24 p.m. MDT, and 9:24 p.m. PDT.