August is late summer in Michigan — the harvest is at full flood, the goldenrod and asters begin their bloom, and fall migration quietly gathers. Warm nights and the Perseid meteors make it one of the best months for the dark northern skies.
Week by week in August
July 30 – August 5
- The goldenrods begin to ignite the roadsides and fields, the season's most important late nectar source for pollinators and monarchs.
- Common nighthawks begin streaming over in loose evening flocks, an early sign of the gathering fall migration.
- Harvest at full tilt and pull and cure onions and garlic once their tops fall over, drying them in a warm, airy spot.
August 6–12
- The Perseid meteor shower peaks around August 12 — one of the year's best, with dozens of bright, swift meteors an hour after midnight from a dark site.
- The markets reach their fullest — sweet corn and tomatoes at their peak, with melons, blueberries, peaches, and the first winter squash.
- The final monarch generation matures — the special super-generation that will fly all the way to central Mexico, fueling on the goldenrod.
August 13–19
- Shorebird migration peaks on the Lake Erie marshes and mudflats, and the first fall warblers drift south in subtler autumn plumage.
- The first asters open behind the goldenrod — New England aster's purple and the sky-blue smooth aster — a pollinator feast.
- A few red maples in wet ground flame early, and scattered black gum and sumac begin to redden, the first previews of fall.
August 20–26
- Purple martins and swallows stage in large pre-migration roosts, and sandhill cranes begin gathering into flocks in the fields and marshes.
- The southward monarch drift gets underway as they gather along the Lake Michigan and Lake Erie shorelines, fueling on goldenrod and asters.
- Peaches, plums, and the first early apples arrive from the fruit belt as the late-summer harvest peaks.
August 27 – September 2
- Common nighthawks pour over at dusk in loose flocks, and the first big push of fall warblers and flycatchers moves through the woods.
- Goldenrod and the building asters reach their stride, the fields awash in yellow and purple and humming with pollinators.
- Sow a last round of quick fall greens, spinach, and radishes in the south, and start planning cover crops for cleared beds.
Birds This Month
August is when fall migration gets seriously underway, even as summer lingers. Shorebird migration is at its peak — Arctic-nesting sandpipers, plovers, yellowlegs, dowitchers, and sanderlings stop on mudflats, beaches, and the Lake Erie marshes such as Pointe Mouillee, one of the state's premier shorebird sites. The first wave of warblers drifts south in subtler fall plumage, along with flycatchers, vireos, and the first nighthawks, which stream over in loose evening flocks late in the month.
Ruby-throated hummingbirds are at peak numbers and feeding voraciously to fuel their coming migration, so keep nectar fresh. Common nighthawks, chimney swifts, and swallows gather and move, and purple martins stage in large roosts before departing. On the northern lakes, young loons are nearly grown, and sandhill cranes begin to gather into pre-migration flocks in the fields and marshes. Keep feeders stocked and watch the skies and shorelines for the building movement.
What's Blooming
August is the start of the great late-summer and fall bloom in Michigan. The goldenrods ignite roadsides, old fields, and prairies in waves of yellow — Canada, tall, gray, stiff, and showy goldenrod — and the first asters open behind them: New England aster's purple, white heath aster, and the sky-blue smooth aster. They are the season's most important late nectar source for pollinators and migrating monarchs.
The prairies and wet meadows hold their peak too: blazing star, ironweed, Joe-Pye weed, boneset, tall coneflower, cup plant, cardinal flower, and great blue lobelia in the wet ground, with sunflowers and sneezeweed adding color. On the dunes the late shoreline flora persists. In gardens, this is the season of black-eyed Susans, phlox, sedum, and the first mums. A restored prairie or fen in August is at its fullest, loudest, most pollinator-rich moment of the year.
Garden This Month
August is peak harvest in the Michigan garden, the tables overflowing. Tomatoes, peppers, eggplant, sweet corn, summer squash, cucumbers, green beans, melons, onions, garlic, and the first winter squash all come in. Pick daily to keep production going, preserve the surplus, and keep watering consistently to prevent cracked tomatoes and bitter cucumbers in the heat. Pull and cure onions and garlic once their tops fall over, drying them in a warm, airy spot.
Keep the fall garden going: early in the month, there's still time in the south to sow quick spinach, lettuce, arugula, radishes, and Asian greens for autumn, and to set out fall brassica transplants. Scout for late-season pests and diseases — late blight, powdery mildew, squash bugs, and hornworms — and remove affected foliage. Deadhead and water flowers through dry spells, and start planning which beds to plant with a fall cover crop after the summer crops finish.
Zone 5b (much of the lower peninsula): harvest at full tilt and finish fall plantings early in the month — sow quick greens, spinach, lettuce, and radishes for autumn, and keep tomatoes and peppers watered through any late heat.
Zone 6a (southwest lakeshore & far south): the long-season warmth lets you keep sowing fall greens and roots through August and into early September for a generous autumn harvest well before frost.
What's at the Farmers Market
August is the most abundant market month of the Michigan year, the stalls heaped with the full summer harvest. Sweet corn and tomatoes are at their peak, joined by peppers, eggplant, summer squash, zucchini, cucumbers, green beans, melons, new potatoes, onions, garlic, and the first winter squash. Blueberries continue strong from the southwest, the tart cherry harvest wraps up, and peaches, plums, and the first early apples arrive from the fruit belt.
Late-summer raspberries and blackberries ripen, and the first concord and table grapes appear toward month's end. Buy sweet corn the day you'll eat it and keep it husked and refrigerated; store tomatoes stem-side down at room temperature, never the fridge, which turns them mealy. Choose firm, fragrant peaches and let them finish ripening on the counter. Pick the heaviest melons that smell sweet at the stem end. The markets are at their fullest, freshest, and most varied of the entire season.
Night Sky This Month
August is one of the best stargazing months in Michigan, with warm, comfortable nights, true darkness returning earlier, and the summer Milky Way at its glorious best. The Summer Triangle of Vega, Deneb, and Altair stands directly overhead, and the galaxy's glowing band runs from Cassiopeia in the north through Cygnus overhead down to the rich star clouds of Sagittarius and Scorpius in the south.
The marquee event is the Perseid meteor shower, peaking around August 12 — one of the year's best, producing dozens of bright, swift meteors an hour from a dark site, radiating from Perseus in the northeast and best after midnight. For the darkest skies and the richest Milky Way, head to the Headlands International Dark Sky Park near Mackinaw City or the Keweenaw Dark Sky Park in the U.P. The far north may also catch summer aurora. The printable Michigan night-sky guide lists this year's exact Perseid peak, planet positions, and aurora outlook for your area.
Butterflies & Pollinators
August is a top butterfly month in Michigan, and the most important for monarchs. The final summer generation matures now, and these are the special 'super-generation' that will not breed but will instead fly all the way to central Mexico — they begin building numbers and fueling up on the blooming goldenrod, asters, and Joe-Pye weed that carpet the late-summer fields. By late August the southward drift is underway, and monarchs gather along the Lake Michigan and Lake Erie shorelines.
The meadows and prairies still teem with great spangled fritillaries, swallowtails, painted ladies, red admirals, buckeyes (which push north in late summer), and a full cast of skippers, alongside viceroys, red-spotted purples, and question marks. The blooming goldenrod is the single richest nectar source of the season — a stand on a warm, sunny afternoon hums with butterflies, bees, and other pollinators. Leave the goldenrod and asters standing to fuel the great monarch migration about to begin.
What to plant for them is in the Michigan native plants guide
Trees This Month
August trees are in mature, late-summer green, but the first hints of the turn appear. The fruit and nut crop ripens fully: black cherries hang dark and abundant for the waxwings and robins, oak acorns and hickory nuts swell toward their fall drop, and the orchard apples and peaches color and sweeten across the fruit belt. The staghorn sumac sets its deep-red fuzzy fruit clusters along roadsides.
Stressed and early-turning trees show the first color — a few red maples in wet ground flame early, and scattered black gum and sumac begin to redden by late month, the earliest previews of the fall display to come. The conifers' new growth has fully hardened, and the jack pines hold their closed cones over the Grayling plains. The days are visibly shortening, and the trees begin the slow internal shift, drawing energy back from the leaves, that will burst into the famous Michigan autumn color over the next two months.
The Michigan native plants guide covers what grows with them
Weather & Daylight
Across Michigan, a typical August day averages a high near 78°F and a low near 56°F, with about 3.3 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
Still warm and humid with highs near 80, though a touch less intense, and frequent thunderstorms breaking up the heavy air.
| Average high | 78°F |
|---|---|
| Average low | 56°F |
| Precipitation | 3.3 in |
| Sunrise (mid-month) | 6:44 ET |
| Sunset (mid-month) | 20:44 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 Michigan's next month turns — what's arriving, blooming, and worth a night outside.
Go deeper with the Michigan guides
The complete Michigan birding, native-plant, and night-sky references — or the whole year, week by week, in one book.
Same month elsewhere: August in Minnesota · August in Mississippi · August in Missouri