Painted lady butterflies (above) are southwestern in origin. They apparently move northward each year and may do so in large numbers in some years. They are irruptive migrants and it’s thought their migrations are weather related, e.g., El Nino. I’ve seen several in the past week.
Painted ladies (Vanessa cardui) may be confused with a more local butterfly within the same genus, American lady (Vanessa virginiensis). American ladies show a white spot in a larger orange rectangular spot on their forewings (it’s visible from above and below). Painted ladies do not have the white spot.
American ladies have two large eyespots on the undersides of their hindwing. Painted lady has four smaller eyespots in the same location.
Not to disappoint, but painted lady butterflies are sold through biological supply outlets as eggs or larvae in kits to raise in classrooms and elsewhere. Some butterflies that you might see out in your garden may be butterflies released through those means.