Happy Halloween Posted on October 16, 2020 at 8:52 am.Written by Blyann Johnson The hours to Trick-or-Treat in the City of Osseo will be from 4:30 to 7:00 p.m. on Saturday, October 31st. Those of you choosing to participate, please turn your porch light on for all the little ghosts & goblins. Have a Happy and Safe Halloween.