Monarch Butterflies in New Hampshire: identification guide and best places to start

1. What time of year can you see monarch butterflies in New Hampshire?

Monarchs arrive in southern New Hampshire around late May to early June. They produce several generations through the summer, with the last generation migrating south in August through October. The best odds for spotting them are in mid-September during the peak migration. Warm, sunny days after a cold front increase activity. Check out New Hampshire's wildlife resources for regional phenology.

In New Hampshire, monarch butterflies sightings usually improve when you slow down and match your first stop to where people are most likely to notice them. Use the state wildlife hub and the route guide to narrow your first area, then check access, weather, and distance before you settle in. A short walk with one clear viewing plan often beats covering too much ground, especially when habitat changes fast from open edges to brush, wetlands, timber, shoreline, or neighborhood cover.

2. Where are the best places to find monarch butterflies in New Hampshire?

Focus on open, sunny areas with abundant milkweed and nectar flowers. Good bets include the fields of New Hampshire state parks, wildlife refuges like Great Bay National Wildlife Refuge, and group gardens. Also check roadsides and powerline cuts where milkweed grows. Start in the southern part of the state, where monarchs arrive first.

3. How do you identify a monarch butterfly in New Hampshire?

Monarchs have bright orange wings with thick black veins and a black border dotted with white spots. The underside is a paler orange with dark veins. The caterpillar is striped yellow, black, and white and feeds only on milkweed. The viceroy butterfly looks similar but has a black line across the hindwing and is slightly smaller. Learn more about monarch identification.

See our state animal guide for the next step.

4. What do monarch butterflies eat in New Hampshire?

Caterpillars eat only milkweed leaves, which makes the adults toxic to predators. Adults feed on nectar from flowers like goldenrod, asters, joe-pye weed, and butterfly bush. Planting these in your yard can attract monarchs. For more tips, see our monarch butterfly hub.

5. How long do monarch butterflies stay in New Hampshire?

Monarchs are present from late May through October. The summer generation lives 2-5 weeks, but the migratory generation (born late summer) can live 6-8 months. They arrive in waves, so you can see them throughout the season. Cool, wet summers may delay arrival.