We visited Patzcuaro on the return from the mountains, traveled more directly on the road to Mexico DF exiting to the south to access roads near the butterflies. We know about the California (State) gatherings of the Mariposas Monarchas, but on this forum, are their other Mexican views on the subject. Yes it gets cold, our young men who directed us on our trip (and skipped school to do so) showed us the thickness of the ice on a barrell of water, about 1/2 inch thick. A trip one never forgets! It's several thousand feet higher, we likely got to over 11,000 feet.