To see Monarch adults, pupae, Monarch Watch has photos. Big Sur California has a
Monarch Walk every year. Their site is informative also.
Monarchs are the only butterfly to commute such long distances with the season change. They return to their winter roosts and sometimes even to the same tree. Individual butterflies make the round trip from the Great Lakes to Mexico once. the Monarchs we see the following fall are their great-grandchildren.
The stages they go through are egg, caterpillar, pupa/chrysalis and adult butterfly.
The eggs hatch in 5 to 10 days and the caterpillar eats the egg shell.
They eat milkweed and as they grow out of their skin/cuticle, they molt. They eat that skin and grow another cuticle. This happens 4-times.
After the 4th molt, the caterpillar creates a green chrysalis that hangs in shade under a leaf for 2-weeks. When the butterfly has developed, its chrysalis becomes clear, revealing the butterfly within. Its legs move down splitting the chrysalis. The legs harden.
There are photos of the process here.
The resulting butterfly weighs one gram. It will fly to Mexico for the winter.
The North America Butterfly Association site says that when weather is bad, butterflies hunker under leaves or between blades of grass and sleep.
Monarch Butterfly U.S.A. is one of the best designed and most informative sites I found. It answers the life cycle question that many ask, "How long do they live?"
The entire lifecycle lasts 6 to 8 weeks: Four days inside the egg, 2-weeks as a caterpillar, 10-days in the pupa/chrysalis, 2-6-weeks as an adult butterfly.
Monarch females lay around 700 eggs over a period of 2-to-4-weeks, one egg at a time. Monarch Lab at the University of Minnesota has this information and projectsfor teachers and schools.
Ilse Hoppenberg's videos on YouTube are extraordinary. Watch the caterpillar emerge from the egg, the caterpillar molt, become a pupa and then emerge as a butterfly. Outstanding!