August is late summer in Indiana — the hottest, most humid stretch giving way to the first cool nights, the goldenrod and asters beginning, the fall bird migration quietly underway, and the farm stands at their peak with tomatoes, sweet corn, and melons. The monarchs begin building toward their great southward journey.
Week by week in August
July 30 – August 5
- Common nighthawks begin streaming over the towns in loose evening flocks, an early sign of fall migration.
- Monarch numbers stay high as the late-summer generation that will migrate to Mexico begins to emerge.
- Markets hit peak abundance — tomatoes of every color, sweet corn, melons, peppers, and the juiciest southern peaches.
August 6–12
- The Perseid meteor shower peaks around August 12, one of the year's best — dozens of swift meteors an hour after midnight from a dark site.
- Shorebirds build at Goose Pond and great egrets gather in big post-breeding numbers in the wetlands.
- Monarchs begin staging and drifting south, gathering along the Lake Michigan shore at Indiana Dunes.
August 13–19
- The first goldenrod and tall ironweed bloom at Goose Pond as the prairie tips from summer toward fall.
- Pawpaws ripen in the bottomland understory and black walnuts begin dropping their green-husked nuts.
- Transplant fall brassicas and sow a second round of lettuce, spinach, and radishes in the cooling soil.
August 20–26
- Purple martins stage in huge pre-migration roosts and ruby-throated hummingbirds reach peak abundance at feeders.
- Black gum flecks early crimson in the wet woods, the first hint of the fall color to come.
- The first winter squash and early apples appear alongside the peak of melons, tomatoes, and peaches.
August 27 – September 2
- Fall warbler migration trickles south through the woods, drabber and quieter than spring but in good numbers.
- New England aster opens deep violet and the goldenrod sweeps spread — the indispensable late-season nectar source.
- The migrating monarchs nectar on goldenrod and aster, fueling the long journey toward Mexico.
Birds This Month
August is when Indiana's fall migration gets seriously underway, even as the summer heat lingers. Shorebirds are the early stars: the mudflats at Goose Pond FWA and exposed reservoir shorelines fill with lesser and greater yellowlegs, pectoral, least, semipalmated, and solitary sandpipers, and the occasional rarity. Great egrets gather in big post-breeding numbers in the wetlands, joined by little blue herons and the chance of an out-of-range wader.
The first songbirds slip south too: warblers begin trickling through the woods (quieter and duller than spring), and common nighthawks stream over the towns in loose evening flocks late in the month — one of the season's signature sights. Ruby-throated hummingbirds are at peak abundance at feeders as the year's young and migrants from the north pass through; keep nectar fresh. Purple martins stage in huge pre-migration roosts, and American goldfinches nest on, feeding their late broods on thistle down.
What's Blooming
August carries Indiana's prairies into their late-summer phase as the yellows and purples of fall begin. The grasslands at Goose Pond blaze with black-eyed Susan, tall coreopsis, cup plant, compass plant, prairie blazing star, and the first sweeps of goldenrod and tall ironweed, while the big bluestem and Indian grass turn their flowering heads bronze. Along the wet margins, joe-pye weed, cardinal flower, great blue lobelia, and swamp milkweed draw butterflies and hummingbirds.
Roadsides and old fields fill with goldenrod, Queen Anne's lace, chicory, partridge pea, and the first asters, and the woodland edges show the orange spurs of jewelweed. In gardens, the sunflowers, zinnias, black-eyed Susans, coneflowers, phlox, and Russian sage are at their height, the first sedums blush pink, and the dahlias hit full stride — the garden lush but tipping, by month's end, toward the look of fall.
Garden This Month
August is the height of the harvest and the launch of the fall garden. The summer crops pour in — tomatoes, peppers, sweet corn, beans, cucumbers, summer squash, eggplant, and melons — so the work is picking, preserving, and keeping plants watered through the heat. Stay ahead of the late-summer pests and diseases: keep removing blighted lower tomato leaves, watch for squash vine borer and stink bugs, and pick everything regularly to keep production going.
Crucially, this is the month to plant the fall garden. Transplant fall broccoli, cabbage, kale, collards, and Brussels sprouts, and direct-sow a second crop of lettuce, spinach, arugula, radishes, turnips, beets, and carrots into the warm soil — they'll mature in the cool of fall and sweeten with the first frosts. Keep new seedlings shaded and well watered to germinate in the heat. In the flower garden, keep deadheading and watering, and order spring-flowering bulbs now for fall planting.
Zone 5b (northern Indiana & the lake region): with the first frost only about ten weeks off, prioritize the fall crops — transplant fall brassicas now and direct-sow spinach, lettuce, radishes, and turnips for an autumn harvest. Keep summer crops watered through any late heat.
Zone 6a (central Indiana): peak harvest continues — keep picking and preserving. Transplant fall broccoli, cabbage, and kale, and sow fall lettuce, spinach, beets, and radishes in the cooling soil for an autumn and early-winter crop.
Zone 6b (the southern Ohio River counties): the long southern season means a generous fall window — set out fall brassicas, sow a full second round of greens and root crops, and even try a quick crop of bush beans. Provide shade for tender seedlings in the August heat.
What's at the Farmers Market
August is the absolute peak of the Indiana market season, the tables groaning with the summer harvest. Vine-ripe tomatoes of every color, sweet corn at its best, and the celebrated southwestern Indiana melons — cantaloupes and watermelons — are the headliners, alongside sweet and hot peppers, eggplant, green beans, okra, cucumbers, summer squash, new potatoes, onions, garlic, and the first winter squash and tomatillos.
The fruit is superb: peaches from the southern orchards at their juicy peak, plus blackberries, late blueberries, the first early apples, and plums. Cut flowers — sunflowers, zinnias, and dahlias — and fresh herbs and honey fill out the stands. Choose heavy, fragrant melons and store them whole at room temperature; pick firm, glossy peppers and eggplant; and let firm peaches finish softening on the counter before refrigerating. Keep tomatoes off the fridge shelf to protect their flavor.
Night Sky This Month
August is the favorite stargazing month of the Indiana summer, with warm nights, earlier darkness than June or July, and the famous Perseid meteor shower. The Perseid meteor shower peaks around August 12, one of the year's best and most reliable, throwing dozens of swift, often bright meteors an hour from a dark site after midnight — try the Hoosier National Forest, Goose Pond, or any spot away from the Indianapolis glow. The radiant lies in Perseus, rising in the northeast.
The rest of the sky is glorious: the Summer Triangle of Vega, Deneb, and Altair stands high overhead, and the summer Milky Way arches across the whole sky from Sagittarius and Scorpius in the south up through Cygnus, displaying its star clouds and dark rifts beautifully from dark country. This is the best month to trace the galaxy with binoculars. The printable Indiana night-sky guide lists this year's exact Perseid peak timing, the Moon's interference, and planet positions for your location.
Butterflies & Pollinators
August keeps Indiana's butterfly populations near their summer peak while the season's defining event begins: the monarchs start staging for migration. The late-summer generation now emerging is the special "super generation" that will not breed but instead fly all the way to central Mexico; watch for them building in numbers and beginning to drift south and gather at nectar sources late in the month, especially along the Lake Michigan shore at Indiana Dunes, a major fall flyway.
The gardens and prairies still teem with tiger, black, and spicebush swallowtails, great spangled fritillaries, red-spotted purples, common buckeyes, painted ladies, red admirals, and clouds of skippers and sulphurs. The late-season nectar plants are the magnets now — goldenrod, ironweed, joe-pye weed, tall coreopsis, zinnias, and tithonia — fueling both the resident butterflies and the gathering migrants. Leave the goldenrod and asters standing; they are the fuel that powers the monarchs' long journey south.
What to plant for them is in the Indiana native plants guide
Trees This Month
August's trees hold their deep summer green, but the first hints of the turn appear by month's end. A few species jump the gun on fall color: black gum (tupelo) flecks crimson early in the wet woods, the invasive tree-of-heaven and stressed buckeyes yellow and drop, and drought-stressed tulip trees and birches shed scorched inner leaves. The sourwood and sumac begin to blush red along the edges.
This is the great fruiting and mast season. The pawpaws ripen in the bottomland understory, the black walnuts drop their green husked nuts, the hickories and oaks swell their nuts and acorns toward the fall mast that feeds the deer, turkeys, and squirrels, and the persimmons of the southern hills harden toward their post-frost ripeness. The elderberries hang heavy and dark in the wet thickets, and the wild grapes purple on their vines. The droning of annual cicadas fills the hot afternoons, the sound of late Indiana summer.
Weather & Daylight
Across Indiana, a typical August day averages a high near 84°F and a low near 62°F, with about 3.6 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
Still hot and heavy at 84 by day, nights near 62, though rains ease slightly from July's drenching, mugginess lingering after dark.
| Average high | 84°F |
|---|---|
| Average low | 62°F |
| Precipitation | 3.6 in |
| Sunrise (mid-month) | 6:56 ET |
| Sunset (mid-month) | 20:43 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).
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One short note when Indiana's next month turns — what's arriving, blooming, and worth a night outside.
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Same month elsewhere: August in Iowa · August in Kansas · August in Kentucky