Meet
a Slow-growing Monarch
and Explore Climate Connections
Yes, cool temperatures and slow-growing monarchs may be one reason monarchs are apparently scarce this fall. Many monarchs may still be in the egg, larva, or chrysalis stage. If they grow into adults in time they'll join the migration later.
The monarchs may have had a slow start at the beginning of the breeding season due to cool temperatures last spring, too.
If monarchs arrive early enough and temperatures are warm enough, they have time to produce three generations at northern latitudes. The population grows larger and larger with each new generation.
If monarchs arrive late and/or have cool temperatures, there may only be time for two generations in the north.
Take Note: Nobody knows yet if the population is truly small. We will learn more as the season unfolds and, when the monarchs reach Mexico, scientists will measure the size of the winter colonies for an annual comparison.
What's more, right now monarchs in the south are producing another new generation and those butterflies will join to the population, too.
