Observations on overwintering monarch butterflies in California and Hawaii Expositor Staff Apr 01, 2015 - 5 min read The sign at the entrance to the Monarch Grove Sanctuary in Pacific Grove, California. The sign at the entrance to the Monarch Grove Sanctuary in Pacific Grove, California. This post is for paying subscribers only Subscribe now and have access to all our stories, enjoy exclusive content and stay up to date with constant updates. Subscribe now Already a member? Sign in