April is the surge of spring in Illinois — the floodplain woods turn blue with bluebells, the first warblers trickle onto the Chicago lakefront, and the whole landscape leafs out and greens. It is a fast, exhilarating month that builds toward the migration peak of May.
Week by week in April
April 2–8
- Virginia bluebells begin carpeting the Illinois and Mississippi floodplain woods in sheets of sky blue — the state's signature spring display.
- Early migrant songbirds pour in — brown thrashers, house wrens, blue-gray gnatcatchers, and the first yellow-rumped and palm warblers.
- Plant the full cool-season garden — peas, lettuce, brassicas, carrots, beets, and potatoes — in the warming soil.
April 9–15
- The spring-ephemeral show peaks: large-flowered trillium, Dutchman's breeches, wild geranium, and mayapple fill the rich woods.
- The Montrose Point 'Magic Hedge' on the Chicago lakefront begins drawing migrants, a preview of the May explosion to come.
- Redbud and flowering dogwood color the Shawnee hills, while orchard apples and cherries burst into pink and white bloom.
April 16–22
- The Lyrid meteor shower peaks around April 22, a modest but reliable shower radiating from near bright Vega after midnight.
- Grassland birds return to Midewin and Nachusa — eastern meadowlarks, savannah sparrows, and the first bobolinks and dickcissels.
- The first eastern tiger swallowtails appear in the warmer south, joining the spring azures and overwintered mourning cloaks.
April 23–29
- Hang oriole and hummingbird feeders now — ruby-throated hummingbirds and Baltimore orioles arrive right at the turn into May.
- The first monarchs reach southern and central Illinois, the females laying eggs on the newly emerging milkweed.
- In the far south the last frost has passed — set out tomatoes, peppers, and squash, while the north waits a few weeks more.
Birds This Month
April is when spring migration accelerates hard. The early-season songbirds arrive in force: eastern phoebes, blue-gray gnatcatchers, brown thrashers, house wrens, chipping sparrows, and the first trickle of warblers — yellow-rumped, palm, and pine warblers lead the wave, with louisiana waterthrush singing along southern streams. By late April the famous Montrose Point 'Magic Hedge' on the Chicago lakefront begins to draw migrants, a preview of the May explosion to come.
The prairie and grassland birds return to claim their territories: eastern meadowlarks, field and savannah sparrows, and the first bobolinks and dickcissels at Midewin and Nachusa. Wetlands fill with great egrets, great blue herons on their rookeries, ospreys back on the rivers, and a steady passage of shorebirds on the mudflats at Emiquon. Hummingbird and oriole feeders should go up late in the month — ruby-throated hummingbirds and Baltimore orioles arrive right at the turn into May.
What's Blooming
April is the climax of the spring-ephemeral show, and Illinois's signature display is Virginia bluebells carpeting the river-bottom forests of the Illinois and Mississippi floodplains in sheets of sky blue. The rich woods fill with large-flowered trillium, wild geranium, Dutchman's breeches, spring beauty, trout lily, mayapple unfurling its umbrellas, wild ginger, bellwort, and the white stars of rue anemone. Bloodroot and hepatica finish as the later species peak.
On the dry prairies and savannas, the fuzzy lavender pasque flower opens in the northern grasslands, the earliest prairie bloom, with the nodding pink-and-cream prairie smoke just beginning to follow it into its main May flowering. Gardens hit full stride with daffodils, tulips, grape hyacinth, and the first creeping phlox. The ephemerals vanish fast once the canopy closes, so April — especially the first three weeks — is the time to walk a floodplain woodland and catch the bluebells at their peak.
Garden This Month
April is a big planting month in Illinois, but timed around the last-frost date, which falls in mid-to-late April in the far south and mid-May in the north. Plant the cool-season garden in earnest: peas, lettuce, spinach, radishes, carrots, beets, onions, potatoes, broccoli, cabbage, and kale all thrive in the cool soil. Keep tomato, pepper, and eggplant seedlings hardening off for transplant after frost.
This is the month to plant bare-root trees, shrubs, and perennials while they're dormant, to divide overgrown perennials as they break ground, and to top-dress beds with compost and mulch. Hold off on cutting back ornamental grasses and perennial stems until consistent warm weather releases overwintering pollinators. Pull early weeds before they set seed, and resist setting out frost-tender crops too early — a late-April or early-May freeze still strikes the northern two-thirds of the state most years.
Zone 5b (Chicago metro & northern Illinois): plant the full cool-season garden — peas, lettuce, brassicas, carrots, beets, onions, and potatoes — and harden off warm-season transplants, but hold tomatoes and peppers until mid-to-late May, as the last frost is still weeks away.
Zone 6b (south-central Illinois): cool-season crops are growing fast; near month's end you can start setting out the hardiest warm-season transplants under cover, watching the forecast for a late frost.
Zone 7a (far southern Illinois / 'Little Egypt'): the last frost passes mid-month — set out tomatoes, peppers, and squash in the second half of April, and direct-sow beans and corn into the warming soil ahead of the rest of the state.
What's at the Farmers Market
April is when Illinois farmers markets begin reopening and the first true spring harvest arrives. Asparagus is the headliner late in the month — local spears at their tender, sweet best for just a few weeks — alongside rhubarb and an expanding supply of spring greens: spinach, lettuce, arugula, radishes, green onions, and overwintered kale. Wild ramps (wild leeks) appear from the woods.
This is also the start of the biggest plant-sale season of the year — markets and nurseries fill with vegetable seedlings, herbs, hanging baskets, and native perennials for gardeners racing toward the frost date. The last of the spring maple syrup and stored apples are still around. Choose asparagus with tight, firm tips and snappy stalks and stand it upright in a little water in the fridge; pick the freshest greens and use them within a few days. The markets grow more abundant by the week.
Night Sky This Month
April's milder, lengthening nights make for comfortable stargazing under the spring sky. Leo the Lion stands high in the south with the bright star Regulus at the base of its 'sickle,' the Big Dipper rides nearly overhead, and its curving handle 'arcs to Arcturus,' the brilliant orange star of Boötes climbing in the east, then 'spikes to Spica' in Virgo. This is galaxy season — the realm of the Virgo Cluster — best explored with a telescope from a dark site.
The Lyrid meteor shower peaks around April 22, a modest but reliable shower whose 15 or so meteors an hour radiate from near the bright star Vega, best viewed after midnight from somewhere dark like the Shawnee National Forest. The printable Illinois night-sky guide gives this year's exact Lyrid peak date, moon phase, and planet positions for your part of the state.
Butterflies & Pollinators
April butterflies multiply quickly as the weather warms. The overwintered mourning cloaks, commas, and question marks are joined by a fresh generation of newly emerged species: tiny powder-blue spring azures, cabbage whites, and the first clouded and orange sulphurs over open ground. The earliest red admirals and painted ladies arrive as migrants from the south, sometimes in large numbers in a big-flight year, and the first eastern tiger swallowtails appear at the very end of the month in the warmer south.
This is the leading edge of the monarch return — the first individuals reach southern and central Illinois in late April, and the females begin laying eggs on the newly emerging milkweed. Watch sunny woodland edges, fencerows, and the first prairie and garden blooms for nectaring butterflies on warm afternoons, and make sure native milkweed is up and growing for the arriving monarchs.
What to plant for them is in the Illinois native plants guide
Trees This Month
April is leaf-out and the peak of tree flowering across Illinois. The woodland edges glow with the magenta of native eastern redbud and the white of flowering dogwood and serviceberry — a signature combination in the Shawnee hills of the south. Wild plum and chokecherry foam white along fencerows, and orchard apples, crabapples, and cherries burst into pink and white bloom.
The canopy fills in from the bottom up: silver and red maples are already leafing, cottonwoods and willows green along the rivers, and by late month the great white and bur oaks and the hickories finally break bud and unfurl, dusting the air with pollen. In the far southern swamps, the bald cypress push out their soft, feathery new needles, turning the gray winter swamps a fresh, bright green.
The Illinois native plants guide covers what grows with them
Weather & Daylight
Across Illinois, a typical April day averages a high near 64°F and a low near 41°F, with about 4.2 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
Mild and often damp, with highs in the low 60s and the year's heaviest rain soaking newly greening ground.
| Average high | 64°F |
|---|---|
| Average low | 41°F |
| Precipitation | 4.2 in |
| Sunrise (mid-month) | 6:18 CT |
| Sunset (mid-month) | 19:34 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: April in Indiana · April in Iowa · April in Kansas