May is the peak of the Indiana spring — the warbler migration crests, the tulip trees flower in the canopy, the last frost finally releases the gardens, and the woods and prairies fill with birdsong and color. It is the single richest birding month of the year, especially along the Lake Michigan shore at Indiana Dunes.
Week by week in May
April 30 – May 6
- The warbler migration surges — magnolia, chestnut-sided, and blackburnian warblers pour through, best at Indiana Dunes on Lake Michigan.
- Wild geranium, wild columbine, and fire pink open as the spring ephemerals finish and the peonies push up in gardens.
- Asparagus is the star of the reopened markets, at its tender, sweet best for just a few weeks.
May 7–13
- Warbler migration peaks; rose-breasted grosbeaks, Baltimore orioles, scarlet tanagers, and indigo buntings flood in with them.
- The tulip tree lifts its large green-and-orange tulip-shaped flowers high in the canopy.
- The first monarchs reach the state to lay eggs on emerging milkweed, joined by zebra swallowtails in the southern pawpaw woods.
May 14–20
- Cerulean warblers settle to breed in the mature hardwoods of the south-central hills, a stronghold for the sky-blue canopy singer.
- The peonies — the Indiana state flower — reach their fragrant peak, and wild lupine blooms in the Dunes oak savannas.
- After the mid-May frost date passes, set out tomatoes, peppers, and squash and direct-sow beans, corn, and melons into warm soil.
May 21–27
- Dickcissels, bobolinks, and eastern meadowlarks sing over the Goose Pond grasslands as the breeding season settles in.
- Strawberries ripen at the markets, picked dead-ripe and intensely sweet, alongside abundant spring greens.
- Black locust drips fragrant white flower clusters and the cottonwoods release drifting white seed-cotton along the rivers.
May 28 – June 3
- The breeding chorus is at its fullest — wood thrushes, indigo buntings, and scarlet tanagers sing from dawn forest and field.
- Great spangled fritillaries emerge and red-spotted purples bask on the dirt roads and trails of the southern forests.
- The prairie bloom begins at Goose Pond with butterfly milkweed blazing orange and the first purple coneflower.
Birds This Month
May is the best birding month in Indiana, and the headline is the warbler migration. Wave after wave of tiny, brilliant songbirds pour north through the state — magnolia, chestnut-sided, blackburnian, black-throated green, Cape May, bay-breasted, Tennessee, and many more — peaking in the first three weeks. The premier spot is Indiana Dunes National Park along Lake Michigan, where migrants concentrate against the shoreline, but every wooded park and yard fills with birds. South-central forests draw the cerulean warbler, a sky-blue canopy specialist for which Indiana's mature hardwoods are an important stronghold.
Along with warblers come rose-breasted grosbeaks, Baltimore and orchard orioles, scarlet and summer tanagers, indigo buntings, ruby-throated hummingbirds, and a flood of flycatchers, vireos, and thrushes. Eastern whip-poor-wills and chuck-will's-widows call through the southern nights, and grassland birds — bobolinks, dickcissels, and eastern meadowlarks — sing over Goose Pond's prairies. Keep feeders up, and listen at dawn: the spring chorus is at its absolute fullest.
What's Blooming
May carries the wildflower season from the woods out into the open. The last spring ephemerals — large-flowered trillium, wild blue phlox, wild geranium, Solomon's seal, mayapple, and Jack-in-the-pulpit — finish in the shade as the canopy closes, while wild columbine nods on rocky slopes and fire pink glows red in the southern hills. Golden ragwort and Virginia waterleaf fill the woodland edges.
As the trees leaf out, the show shifts to sunnier ground: wild lupine blooms in the sandy oak savannas of Indiana Dunes, spiderwort and wild hyacinth open in prairies and glades, and the first prairie phlox and golden Alexanders appear at Goose Pond. In gardens, the peonies — the Indiana state flower — reach their fragrant peak, the lilacs and irises bloom, and the late tulips finish. This is the lush, generous heart of the flowering year, with something new opening every week.
Garden This Month
May is the big planting month, pivoting on the last-frost date — mid-May for most of Indiana, early May in the south, occasionally later in the far north and lake region. Early in the month, keep planting and harvesting cool-season crops — peas, lettuce, spinach, radishes, carrots, beets, and potatoes — and harden off your warm-season seedlings over a week of increasing outdoor exposure.
Once the frost date passes, set out tomatoes, peppers, eggplant, squash, cucumbers, and basil, and direct-sow beans, corn, melons, and okra into soil that has warmed. Watch the forecast vigilantly — a late frost can still strike the central and northern counties, so keep row cover ready. In the flower garden, plant annuals after frost, divide and move perennials, stake the peonies before they flop in a storm, and mulch beds to hold the moisture the coming summer heat will demand.
Zone 5b (northern Indiana & the lake region): the last frost typically falls mid-May, so harden off warm-season transplants and set out tomatoes, peppers, and squash only after about May 15, watching the forecast for a late cold snap. Keep cool-season crops growing in the meantime.
Zone 6a (central Indiana & Indianapolis): the last frost usually passes in early May. After it, set out tomatoes, peppers, eggplant, and cucurbits, direct-sow beans, corn, and squash into warm soil, and plant warm-season flowers.
Zone 6b (the southern Ohio River counties): frost is past — plant everything. Set out all warm-season transplants, direct-sow beans, corn, melons, and okra, and begin succession-sowing for a continuous harvest as the soil is fully warm.
What's at the Farmers Market
May is when Indiana's farmers markets are open across the state and the spring harvest is in full swing. Asparagus is the star — local spears at their tender, sweet best for just a few weeks — alongside strawberries ripening toward month's end, rhubarb, and an abundance of spring greens: leaf lettuce, spinach, arugula, radishes, green onions, kale, and chard. The first spring herbs and the last of the morels appear, and overwintered green garlic and the first hoop-house cucumbers turn up late in the month.
This is also the biggest plant-sale season of the year: markets and nurseries overflow with vegetable seedlings, herbs, hanging baskets, and native perennials for gardeners planting after the frost date. Eggs and honey are plentiful. Choose asparagus with tight, firm tips and snappy stalks and stand it upright in a little water in the fridge; refrigerate strawberries dry and unwashed and use them within a couple of days.
Night Sky This Month
May's mild nights make for comfortable stargazing, though the nights are shortening fast toward the solstice and full darkness comes late. The spring sky is at its best: the Big Dipper rides high overhead, the bright orange star Arcturus in Boötes commands the eastern sky, and blue-white Spica in Virgo and the keystone of Hercules climb behind it. Late in the night, the first of the Summer Triangle stars, Vega, clears the eastern horizon, and the head of Scorpius with red Antares rises in the southeast.
The Eta Aquariid meteor shower — debris from Halley's Comet — peaks in early May, though its low radiant makes it a modest show from Indiana's latitude, best in the dark hour before dawn. The faint band of the summer Milky Way begins to rise in the late-night southeast, a preview of the season ahead from truly dark sites like the Hoosier National Forest. The printable Indiana night-sky guide lists this year's exact meteor-peak dates and planet positions for your location.
Butterflies & Pollinators
May is when Indiana's butterfly diversity really climbs. The big arrival is the monarch — the first generation moves north into the state through the month, the females laying eggs on emerging milkweed that will produce the summer's home-grown broods. They join a building cast: eastern tiger swallowtails are everywhere along woodland edges, joined by black, spicebush, and zebra swallowtails (the last tied to the pawpaw thickets of the southern bottomlands, where its caterpillars feed). Red admirals and painted ladies arrive as migrants, sometimes in big numbers.
Small butterflies abound — spring azures, eastern tailed-blues, pearl crescents, cabbage whites, and sulphurs dot every open field. The iridescent red-spotted purple begins basking on the dirt roads and trails of the southern forests. Watch wild blue phlox, dame's rocket, blackberry blossom, and the first prairie blooms for nectaring butterflies on warm afternoons. The monarchs laying eggs this month are launching the generations that will eventually make the great fall migration.
What to plant for them is in the Indiana native plants guide
Trees This Month
May is full leaf-out across Indiana, the canopy closing over and the forest floor falling into shade. The signature event is the flowering of the state tree, the tulip tree, which lifts its large, tulip-shaped green-and-orange blossoms high in the crown — easy to miss from the ground until the spent petals litter the trail. In the understory and along the edges, black locust drips fragrant white flower clusters, catalpa prepares its big orchid-like blooms, and the last dogwoods and hawthorns finish.
The oaks complete their late leaf-out and shed pollen, and the black walnut, hickories, and catalpa — the last trees to green up — finally unfurl. In the bottomland woods the pawpaws have set their first fruit, and along the rivers the sycamores and cottonwoods are in full leaf, the cottonwoods soon to release their drifting cottony seed. By late May the canopy is complete, ending the brief sunlit window the spring ephemerals depended on.
Weather & Daylight
Across Indiana, a typical May day averages a high near 74°F and a low near 51°F, with about 4.8 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
Warm and lush, highs near 74 with comfortable 51-degree evenings, rain arriving often but gentler than the cool spring soak.
| Average high | 74°F |
|---|---|
| Average low | 51°F |
| Precipitation | 4.8 in |
| Sunrise (mid-month) | 6:30 ET |
| Sunset (mid-month) | 20:52 ET |
Figures are statewide averages over the 1991–2020 U.S. climate normals; local conditions vary with elevation and distance from the coast. Sunrise and sunset are computed for a midstate point on the 15th (ET).
Next month's version of this page, by email
One short note when Indiana's next month turns — what's arriving, blooming, and worth a night outside.
Go deeper with the Indiana guides
The complete Indiana birding, native-plant, and night-sky references — or the whole year, week by week, in one book.
Same month elsewhere: May in Iowa · May in Kansas · May in Kentucky