June is early summer in Illinois — the prairie grows tall and the first summer wildflowers open, grassland birds are at peak song, and the gardens hit full stride. The migration has passed and the breeding season is in full swing across woods, wetlands, and the great grasslands.
Week by week in June
June 4–10
- At Nachusa, grassland birds sing among the restored bison herd that grazes and shapes the prairie they depend on.
- The first great spangled fritillaries emerge, and monarch caterpillars appear on the milkweed from May's eggs.
- Strawberries hit their peak across the state — choose berries red all the way through and use them within a couple of days.
June 11–17
- Spiderwort, black-eyed Susan, and pale purple coneflower open as the prairie's long summer bloom gets underway.
- Cool-season greens and peas finish and bolt — harvest promptly and replace with heat-tolerant crops as the heat builds.
- On the finest prairie remnants at Nachusa and Midewin, the rare regal fritillary takes flight.
June 18–24
- The summer solstice around the 20th brings the longest days and shortest nights, with the Milky Way starting to arch up after dark.
- Southern catalpa covers itself in showy white orchid-like blooms, and basswood hums with bees.
- The first summer squash, zucchini, new potatoes, and garlic scapes join the strawberries at the stands.
June 25 – July 1
- The dawn chorus begins to taper as adults shift to feeding fledglings; young cardinals and wrens appear in the brush.
- Wild bergamot, butterfly weed, and the first coneflowers color the prairie as June turns to July.
- Start fall brassica and lettuce seedlings in a cool, shaded spot for an autumn crop, and keep everything deeply watered.
Birds This Month
June is the heart of the Illinois breeding season, and the prairies are the place to be. At Nachusa Grasslands, Midewin National Tallgrass Prairie, and Goose Lake Prairie, the grassland specialists are in full voice: bobolinks bubbling in song flights, eastern meadowlarks whistling from posts, dickcissels buzzing everywhere, grasshopper and Henslow's sparrows giving their insect-like songs, and sedge wrens chattering in the wet meadows. Nachusa's restored bison herd grazes among them, shaping the prairie the birds depend on.
In woods and yards, the breeding songbirds are busy: indigo buntings sing from treetops, scarlet tanagers and wood thrushes hold the forest interior, Baltimore orioles tend hanging nests, and ruby-throated hummingbirds work the feeders and flowers. Wetlands hold nesting great egrets, herons, wood ducks, and red-winged blackbirds. The dawn chorus is at its richest and longest of the year — get out early before the songs taper in the heat.
What's Blooming
June is when the Illinois prairie begins its long summer bloom. The early prairie flowers open across the grasslands: spiderwort, golden black-eyed Susan, the white plumes of wild quinine, prairie phlox, pale purple coneflower starting its season, and the flat yellow umbels of native golden alexanders. Common milkweed opens its fragrant pink globes — a magnet for monarchs and a host for their eggs — and butterfly weed blazes orange on dry ground.
In wetlands and along streams, blue flag iris, swamp milkweed, and water hemlock bloom, and the first elderberry flowers foam white along the edges. Woodland openings hold wild bergamot beginning and the last fire pink. In gardens, peonies, roses, daylilies, and clematis are at their height. June is the gateway month — the prairie show that peaks in July and August is just getting started.
Garden This Month
June is the transition from planting to tending in Illinois gardens. Finish setting out any remaining warm-season transplants and direct-sow successions of beans, cucumbers, summer squash, and corn for a staggered harvest. The cool-season crops — lettuce, spinach, peas, and radishes — are finishing and bolting as the days lengthen and warm, so harvest them promptly and replace with heat-tolerant crops.
The real work now is maintenance: mulch beds to conserve moisture and suppress weeds, water deeply and consistently as summer heat sets in, and stake or cage tomatoes before they sprawl. Pinch herbs to keep them bushy, side-dress heavy feeders, and watch for the first squash bugs and cucumber beetles. Deadhead annuals and early perennials to extend the bloom. In the flower garden, this is a fine time to plant warm-season annuals and to keep newly set perennials watered through their first summer.
Zone 5b (Chicago metro & northern Illinois): all danger of frost is past — finish setting out any remaining warm-season transplants, direct-sow beans, corn, cucumbers, and squash, and begin the steady summer watering and mulching the heat will demand.
Zone 6b (south-central Illinois): the garden is in full production — harvest the spring crops before they bolt, succession-sow beans and cucumbers, and keep tomatoes staked and mulched as the heat builds.
What's at the Farmers Market
June markets surge as the early-summer harvest comes in. Strawberries are the June star across Illinois — fully ripe, fragrant, and fleeting — alongside the last of the asparagus and rhubarb. The greens are abundant: lettuce, spinach, chard, kale, and the first head lettuces, with peas, radishes, green onions, garlic scapes, and the season's first summer squash, zucchini, and new potatoes appearing as the month goes on.
Late in June the first tomatoes from hoop houses and the earliest cucumbers show up, hinting at the summer flood to come. Cut flowers — peonies early, then sunflowers and zinnias — fill the stands. Choose strawberries that are red all the way through and use them within a couple of days; pick the firmest squash and crispest greens and refrigerate them promptly. The markets are lively, varied, and growing fuller each week.
Night Sky This Month
June brings the summer solstice around the 20th — the longest days and shortest nights of the year, which makes for the briefest dark-sky window but the mildest, most comfortable viewing. The Summer Triangle of Vega, Deneb, and Altair climbs the eastern sky, and as the sky fully darkens late at night, the glowing band of the Milky Way begins to arch up from the southeast — its star clouds toward the heart of the galaxy in Sagittarius and Scorpius are best seen from a truly dark site.
There's no major meteor shower this month. The orange supergiant Antares, the heart of the Scorpion, sits low in the south. For the Milky Way and the rich star fields of summer, escape to the dark skies of the Shawnee National Forest in far southern Illinois, far from the Chicago light dome.
The printable Illinois night-sky guide lists this year's planet positions and the exact solstice timing for your location.
Butterflies & Pollinators
June butterflies multiply as summer settles in. The monarchs that arrived in May are now producing the first home-grown Illinois brood — watch milkweed for their striped caterpillars and chrysalises. Big eastern tiger swallowtails and black swallowtails patrol prairies, gardens, and woodland edges, and the first great spangled fritillaries emerge to nectar on milkweed and coneflower. On high-quality prairie remnants such as Nachusa and Midewin, the rare regal fritillary takes flight — a true prairie specialist and a flagship of Illinois grassland conservation.
Smaller butterflies abound: pearl crescents, silver-spotted skippers, cabbage whites, and clouded and orange sulphurs dance over open ground, and red-spotted purples and hackberry emperors haunt the woods. With native milkweed and prairie nectar plants in bloom, June is a rewarding month to watch a sunny patch of prairie or garden on a warm afternoon.
What to plant for them is in the Illinois native plants guide
Trees This Month
By June, Illinois's trees are in full, mature leaf and the canopy is dense and dark green. The late-flowering trees take their turn: the southern catalpa covers itself in showy white orchid-like blooms, the tulip tree opens its green-and-orange cup flowers high in the crown, basswood (linden) hangs heavy with fragrant pale flowers that hum with bees, and elderberry foams white along the woodland edges.
The cottonwoods release their drifting white seed 'cotton' along the river bottoms, sometimes piling like snow. The great white and bur oaks, the hickories, black walnut, and the swamp bald cypress are all fully leafed and now setting their developing fruit and nuts. This is the season of maximum green, when the woods, the river forests, and the savanna groves are at their leafy peak before the long, hot push of midsummer.
The Illinois native plants guide covers what grows with them
Weather & Daylight
Across Illinois, a typical June day averages a high near 83°F and a low near 62°F, with about 4.7 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
Summer heat arrives in earnest, highs in the low 80s and muggy nights staying near 62F, rain falling often but briefly.
| Average high | 83°F |
|---|---|
| Average low | 62°F |
| Precipitation | 4.7 in |
| Sunrise (mid-month) | 5:25 CT |
| Sunset (mid-month) | 20:27 CT |
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 (CT).
Next month's version of this page, by email
One short note when Illinois's next month turns — what's arriving, blooming, and worth a night outside.
Go deeper with the Illinois guides
The complete Illinois birding, native-plant, and night-sky references — or the whole year, week by week, in one book.
Same month elsewhere: June in Indiana · June in Iowa · June in Kansas