When do monarchs come to Austin?

Monarchs come through Austin twice a year. In spring they arrive from Mexico in early March and lay eggs on milkweed here, from about mid-March to about the end of April, busiest from mid-March to mid-April. In fall they pass through on the way to Mexico from the last days of September to early November, and the busiest weeks are usually from about 15 October to about 4 November.¹²

The two visits ask different things of a yard: milkweed for the spring, flowers for the fall. Every date on this page comes from a named record, and where a date is a judgement rather than a measurement, it says so.

Spring: the egg season

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.”¹ Monarch Watch puts their departure from the Mexican colonies in “the second week of March.”³

The nearest dated egg record to Austin that we could find is three eggs at Driftwood, Texas (Hays County), on 12 March 2025, reported to Journey North by Chuck Patterson.⁴ Five days later, an observer at Glen Rose reported eggs “on small antelope horn milkweed sprouts.”⁴ Those are single observations, not averages, but they land where the agencies say they should.

The egg season fades as the first generation of the year, raised on milkweed across Texas and the southern states, heads north; Monarch Joint Venture puts that “in approximately late April through May.”⁵ Sightings people have logged on iNaturalist for Travis County show monarchs, at every stage people photograph, present in a long, gentle plateau from about 12 March to about 6 May, with no sharp peak; the busiest single week is 9 to 15 April.² Those records mix adults with the caterpillar photos that peak in April, so they don’t say whether the adults in them are late arrivals from Mexico or the first local butterflies of the year.²⁶ Monarch Joint Venture puts the first generation’s eggs in the southern states “from late March through April.”⁷ “The end of April” as the end of the egg season is this guide’s judgement from that and the April caterpillar peak, not a dated measurement.

What spring asks of you: milkweed that is already up, or at least sprouting, in early March. Not planted in March; up in March. That means nursery plants set out the previous fall. When they leaf out is the open question on the milkweed page: no source gives a leaf-out month for Travis County. The nearest records are eggs on “small antelope horn milkweed sprouts” at Glen Rose on 17 March 2025, and the photographs people have logged on iNaturalist, which show antelope horns and zizotes in Travis County from early or mid March in most years (retrieved 24 September 2026).⁴⁸

Fall: passing through

Texas Parks and Wildlife: monarchs “enter the Texas portion of this flyway during the last days of September. By early November, most have passed through into Mexico.”¹ Wizzie Brown, the Texas A&M AgriLife Extension entomology specialist for Travis County, says: “They usually start heading south through Texas around September into November.”⁹

That is a passage of about six weeks, and inside it there are about three busy weeks. In the Travis County sightings for 2023, 2024 and 2025, the busiest week fell somewhere between 15 October and 4 November in every one of those years, and it moved: 15 to 21 October in 2023, 22 to 28 October in 2024, and 29 October to 4 November in 2025.² Across all years combined, the busiest week is 22 to 28 October, and the two busiest consecutive weeks hold only about 37.6 percent of all fall sightings (retrieved 23 September 2026).² That is why this page names three weeks rather than a date.

Monarch Watch publishes a table of when “good numbers of monarchs should be observed at each latitude,” with the caution that it is “a general guideline.” Its rows give 4 to 16 October for 31 degrees north and 10 to 22 October for 29 degrees; there is no row for Austin’s 30.¹⁰ The observed Austin peak runs about a week later than a line drawn between those rows, so we print the observed weeks.

Most fall monarchs are not laying eggs. Monarch Joint Venture: “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.”⁵ Most, not all. Among the sightings people logged within 40 km of Austin from 2018 to 2025, there were 112 caterpillar records in October against 398 in April.⁶ A study in north Texas found that “fall reproduction is a response to available host plants.”¹¹ So an October caterpillar is real. It was laid here, by a female that was still breeding; which generation she belonged to, no source can say. Count its filaments before you decide what it is: two pairs, a monarch; three, a queen.¹² Watch it on the plant; our house rule is to bring a caterpillar indoors only in spring. And a caterpillar is not what the fall garden is for. What fall asks of you: flowers in bloom from late September into November.

The planting months

The Native Plant Society of Texas: “Fall is the best time for planting milkweed seeds.”¹³ Sow in fall; the seed waits out the winter and comes up in spring. For leaves next March, set out nursery plants in fall, so they are rooted before the spring monarchs arrive. The Travis County extension office: “Fall is the very best time to plant trees, shrubs and perennials.”¹⁴

Seed sown at any other time wants a soak overnight and a cold, damp spell in the refrigerator first. The Wildflower Center gives 14 to 30 days for green milkweed and zizotes, and 30 days for antelope horns, which in its trial gave over 80 percent germination.¹⁵¹⁶¹⁷ Damp, not wet, in a bag with a little damp sand or a paper towel; the Xerces Society describes it as seed “stored under moist conditions in a refrigerator.”¹⁸ The refrigerator, not the freezer (our practice).

The fall nectar perennials go in during fall or early spring; late May still works if you water through the summer. Mike Arnold, who directs The Gardens at Texas A&M, writing on 22 May 2024 about the fall bloomers he was recommending: “now is the time to plant these fall-blooming perennials so they become relatively established before the stressful heat of summer.”⁹

Nursery milkweed goes in the ground in October or November, so it has a winter to root; the three natives are hardy perennials, and the Wildflower Center lists green milkweed as cold tolerant.¹⁵¹⁴ Planted in February or March, cover it on a freezing night (our practice). The freeze dates below are for seedlings raised indoors.

The freeze dates, and the station behind them

The freeze dates here are NOAA’s 1991–2020 climate normals for Austin Bergstrom Airport (station USW00013904), a 24-year record about 10 km from central Austin (10.5 km from the center of ZIP 78704, by our own measurement).¹⁹

• Median last freeze: 12 March. One year in ten, the last freeze comes after 2 April. Plan tender plants from the later date; tender means seedlings raised indoors and greenhouse-soft stock, not the native perennials.¹⁹
• Median first freeze: 16 November. One year in ten, the first freeze comes before 1 November.¹⁹
• Between them, 123.5 days a year reach 90°F or more.¹⁹ The heat, not the cold, is what an Austin planting year is built around.

Austin has three long-running stations, and their freeze dates differ by weeks. We plan from Bergstrom because both of its dates are the latest of the three: its median last freeze, 12 March, and its one-in-ten date, 2 April. Seedlings raised indoors wait for 2 April. Austin 6S’s matching date is 31 March, and Camp Mabry’s is 14 March.¹⁹²⁰²¹

All three are from NOAA’s 1991–2020 normals; NOAA’s completeness flags are S, R and S respectively.¹⁹²⁰²¹ Distances from the center of ZIP 78704, by our own calculation: 10.5 km, 3.7 km and 8.7 km.

Two things the record does not give

A first-sighting date. We looked for a dated first spring sighting of a monarch in Travis County for each year from 2022 to 2026 and found none we could stand behind. Journey North rebuilt its website in early 2026: “All reports in these categories through 2020 have been published, and sightings after that will be published at a future date,” so records may exist that are not yet reachable.²² And Travis County has a few monarch sightings even in January (17, 7 and 10 in the first three weeks of January, all years combined), so a “first sighting of the year” can be a straggler rather than an arrival.²

A promise. Nobody can promise a monarch will find your yard, and we won’t. The dates above are what you can plan by; weather, predators and disease decide the rest.

How we know. The spring and fall dates come from Texas Parks and Wildlife and the Travis County extension office. The busiest weeks come from sightings people have logged on iNaturalist for Travis County; they reflect how many people were out looking as well as how many monarchs were there, and the counts shift a little as people add sightings. The freeze dates are NOAA’s.

The Austin edition puts these dates on a month-by-month calendar beside the plants that fit each window, and adds the safety chapter and the child’s journal. The plants themselves are on the free page Best milkweed for Austin.

Last changed September 24, 2026.