The monarch migration map

The best monarch migration maps are the live ones, drawn from what people report each week: Journey North’s sighting maps, which plot adults, eggs, caterpillars, roosts and milkweed by season, and Monarch Watch’s table of when the fall migration peaks at each latitude.¹² We don’t draw our own map, because a drawn map goes stale and a live one doesn’t. This page says where the monarchs are in each season, with the sources, and where to watch them move.

The live maps

Journey North publishes maps built from public sightings. On its maps page you will find, for the fall season, “Monarch Adult Sighted,” “Monarch Egg Sighted,” “Monarch Larva or Chrysalis Sighted,” “Monarch Fall Roost” and “Milkweed Sighted,” with the spring maps on the same page when the season turns.¹ Journey North moved to Monarch Joint Venture and rebuilt its website in early 2026; its older reports “through 2020 have been published, and sightings after that will be published at a future date,” so some recent years are thinner than they will be.³

Monarch Watch, at the University of Kansas, publishes the table of fall peak dates by latitude that this page quotes below, with the caution that it is “a general guideline” and that “the migration record at specific locations for any given year may differ from this overall pattern.”²

iNaturalist holds photographed sightings that other users confirm; Texas Parks and Wildlife’s monarch page points to it as a place to report.⁴

Winter: the forests in Mexico

The eastern population, the one east of the Rocky Mountains, spends the winter in central Mexico. Monarch Joint Venture: “In Mexico, monarchs roost in oyamel fir forests, which occur in a very small mountainous area in central Mexico. Overwintering sites are about 3000 meters (almost 2 miles) above sea level and are on steep, southwest-facing slopes.” They arrive “beginning in early November.”⁵ In the winter of 2025–26, surveyors found nine colonies, three in Michoacán and six in the State of México, covering 7.24 acres of forest.⁶ Monarch Watch notes that “the monarch colony at El Rosario is usually opened to the public around the 18th of November.”²

The western population winters separately, in groves “along the California coast roughly between Mendocino County in the north, and San Diego County in the South,” in “eucalyptus, Monterey cypress, Monterey pine, and other trees.”⁵ Volunteers counted “approximately 12,260 monarchs” there at the end of 2025; in the 1980s there were “low millions.”⁷

Spring: north through Texas

Monarch Watch: “They leave their Mexican roosts during the second week of March, flying north and east looking for milkweed plants on which to lay their eggs.”⁸ Texas Parks and Wildlife: “Early each March overwintering monarchs begin arriving from their overwintering grounds in Mexico. Seeking emerging milkweeds, they move through Texas laying eggs before dying.”⁴ Monarch Joint Venture: “In March, this generation begins the journey north into Texas and southern states, laying eggs and nectaring as they migrate and breed.” Their offspring “continue the journey from the southern U.S. to recolonize the eastern breeding grounds, migrating north through the central latitudes in approximately late April through May.”⁵

In the West, “adult monarchs west of the Rocky Mountains leave overwintering sites along the California coast (with a small number of sites in Baja California and Arizona) in February and March and head inland in search of milkweed on which to deposit their eggs.”⁵

Summer: the north

Monarch Joint Venture: “Generation 2 eggs are laid throughout much of eastern North America from late April through June. Generations 3 and 4 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).”⁹ “Second and third generations populate the breeding grounds throughout the summer. It is generally the fourth generation” that migrates.⁵ A summer adult lives two to five weeks.⁹ In 2026, Journey North reported the first roosts of the southbound flight on 18 August: “Roost reports have begun in western Minnesota.”¹⁰

Fall: the funnel

“Most monarch butterflies that emerge after about mid August in the eastern U.S. enter reproductive diapause (do not reproduce) and begin to migrate south in search of the overwintering grounds where they have never been before.”⁵ They “travel up to an astonishing 3,000 miles to central Mexico.”⁵

Selected rows from Monarch Watch’s table of when “good numbers of monarchs should be observed at each latitude”; the published table also has rows for 47, 43, 23 and 21 degrees north:²

The last row, in Monarch Watch’s words, “represents the general vicinity of the overwintering colonies.”² The flight narrows as it goes. The U.S. Forest Service: “Eastern North American monarchs fly south using several flyways then merge into a single flyway in Central Texas.”¹¹ Texas Parks and Wildlife describes that flyway as “a 300-mile wide path stretching from Wichita Falls to Eagle Pass,” entered “during the last days of September,” with a second route “along the Texas coast” from “the third week of October to the middle of November.”⁴ Journey North’s roost reports show “two distinct flyways as they travel to Mexico, an Eastern Flyway and a Central Flyway. Only one flyway appears to lead directly to Mexico.”¹² The Texas roosts Journey North named in fall 2025 were at Wichita Falls, Mason and Abilene.¹³ The Texas page has the state in detail.

How the map got drawn

Nobody watched a monarch fly to Mexico. The route was worked out with tags: small numbered stickers on a hind wing, placed by volunteers in fall and found again where the butterfly ended up. Monarch Watch: “Tagging was originally used by Dr. Fred Urquhart of the University of Toronto help locate overwintering monarchs and later to determine where monarchs came from that wintered in Mexico.” It publishes its “Tag recoveries from central Mexico 1993 to 2025 seasons.”¹⁴ Since the program began in 1992, “more than 3 million monarchs have been tagged by thousands of community scientists,” and in 2026 a tag turned up at El Rosario that had been put on a female monarch in Kansas in September 1997.¹⁵

Reporting your own sighting

A dated sighting from your yard, with a photograph, is the same kind of record. Journey North takes reports of adults, eggs, caterpillars, roosts and milkweed; iNaturalist takes photographs and confirms them.¹⁴ Both feed the maps above.

This page is revised when the sources change, not on a schedule. Last checked 23 September 2026.