Warm Fall, Late Sightings
Temperatures across the north have been unusually warm, and appear to have given many late-season monarchs time to complete the life cycle. Monarchs are still being seen, and often in large numbers:

"I saw about 100 monarchs leaving New Hampshire's seacoast today in about an hour of continuous flow. The next morning, I saw lots more warming up and flying." Hampton Beach, New Hampshire: October 9