Last year their numbers were down, but monarch butterflies seem to be making a comeback this summer.
The weather has been perfect for monarchs and the milkweed plants they depend on, said Karen Oberhauser, a biologist at the University of Minnesota.
"A combination of wet and warm, but not too hot," she said. "That's what they like."
Oberhauser said people who want to see more of the distinctive orange-and-black monarchs should plant nectar-bearing flowers.
"Right now coneflowers are blooming, and Joe-Pye weed, and a lot of milkweed species, so if they have some nectar sources and milkweed in their yards, they will not only be seeing more monarchs but they'll be helping them," Oberhauser said.
Oberhauser said weather and habitat are the biggest factors in the health of monarch populations. They depend on nectar from flowers for food, but they breed only on milkweed plants.