09/07/2026
Was surprised to see this caterpillar today!
Had to Google “found a caterpillar in Sept. in Minnesota!”
(Saw a monarch butterfly too, but it didn’t stop for a photo.)
Found this:
The Monarch Caterpillar feeds exclusively on milkweed. Late-season monarchs found in September are part of the famous "super generation" that will emerge as Monarch Butterflies and fly all the way south to Mexico for the winter.
And…
Finding a monarch caterpillar in Minnesota during September is perfectly fine, though it is cutting it close to the end of the breeding season. Recent data from the Minnesota DNR shows that peak migration out of the state typically runs from late August through mid-September, but adult monarchs are routinely spotted well into October—often past the first light freeze.
What to Expect
* The Timeline: The total lifecycle from a caterpillar to an adult butterfly takes about 20 to 30 days.
* The Migration: September and October adults are the "super generation." They live up to 6 to 7 months instead of a few weeks. They will fly thousands of miles south to overwinter in central Mexico.
* The Food: They need fresh milkweed to finish growing into a chrysalis.
