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 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 adult monarchs 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 “Mid-April” as the end of the egg season is this guide’s judgement from those two records, 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. Whether fall-sown plants are up by then is the open question on the milkweed page: no source gives a leaf-out month for Travis County, and the nearest record is eggs on “small antelope horn milkweed sprouts” at Glen Rose on 17 March 2025.⁴

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.”⁶

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 30.⁷ 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.⁸ A study in north Texas found that “fall reproduction is a response to available host plants.”⁹ So an October caterpillar is real; it is just 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.”¹⁰ Sow in fall, so the plants are in the ground and rooting before the spring monarchs arrive.

Green milkweed and zizotes seed sown at any other time wants a soak overnight and 14 to 30 days of cold, damp stratification first, in the Wildflower Center’s instructions.¹¹¹²

The fall nectar perennials go in during late spring. 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.”⁶

Nursery milkweed in pots goes out once the freeze risk has passed. The dates are below.

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).¹³

• Median last freeze: 12 March. One year in ten, the last freeze comes after 2 April. Plan tender plants from the later date.¹³
• Median first freeze: 16 November. One year in ten, the first freeze comes before 1 November.¹³
• Between them, 123.5 days a year reach 90°F or more.¹³ 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. Tender plants wait for 2 April. Austin 6S’s matching date is 31 March, and Camp Mabry’s is 14 March.¹³¹⁴¹⁵

All three are from NOAA’s 1991–2020 normals; NOAA’s completeness flags are S, R and S respectively.¹³¹⁴¹⁵ 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.¹⁶ 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 everything that is in your control.

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.