It is amazing to think about a butterfly being a long-distance migrant, the truly mind-blowing part is that no one butterfly completes the full migration! In fact, each year there are 4 generations of monarch butterflies. The monarchs that spend the winter in the mountains of central Mexico are the final generation of a cycle that begins over each year.

Generation 1

Monarchs in Generation 1 are the offspring of the monarchs that overwinter. They are laid from late March through April in the southern United States and northern Mexico and fly north as adults.

Generation 2

Monarchs in Generation 2 are the grandchildren of the overwintering monarchs. They are laid throughout much of eastern North America from late April through June.

Generations 3 & 4

Monarchs in Generations 3 and 4 are the great and great-great-grandchildren of the overwintering monarchs.

They are laid throughout the northern part of the range of eastern migratory monarchs from late May through July (Generation 3), and late June through August (Generation 4). 

Some generation 3 monarchs emerge early enough to reproduce in the northern part of their breeding range or after moving south. However,  Generation 3 monarchs that emerge late in August will undergo diapause, which is a delayed reproductive maturity. They will migrate to Mexico, as will most Generation 4 monarchs.

The first three generations live 2-6 weeks over the summer, but it is the fourth generation that lives 6-9 months. During September, October, and early November, migratory adults fly to overwintering sites in central Mexico, where they remain from November to March. In March, they begin to journey north, laying the eggs that will become the new Generation 1 along the way.


Migration map

migration cycle

migration by latitude

*Latitude for Chattanooga is 35