August is late high summer in Wyoming — the basins hot and golden, the high meadows still flowering at the top, fall migration building, and the elk beginning to bugle in the mountains by month's end. The harvest peaks in the valleys, and the long, warm, dark nights make it one of the year's best months for the Milky Way and the Perseids.
Week by week in August
July 30 – August 5
- Shorebirds funnel through the drying mudflats of Seedskadee and the reservoirs — sandpipers, dowitchers, yellowlegs, and avocets staging.
- Fresh Wyoming honey begins to flow from the alfalfa and clover bloom as the high-summer vegetable harvest comes in fast.
- The high country's alpine season closes — the last parnassians and alpine fritillaries fly before the cold shuts them down.
August 6–12
- The Perseid meteor shower peaks around August 12, often dozens an hour from a dark Wyoming basin under the blazing summer Milky Way.
- Rabbitbrush begins its brilliant gold across the sagebrush flats as fireweed, aster, and goldenrod hold the late-summer palette.
- Swallows mass on wires and common nighthawks stream south at dusk as fall migration quietly builds across the basins.
August 13–19
- Markets reach their fullest with tomatoes, sweet corn, beans, potatoes, and a deep run of raspberries and frost-sweetened greens.
- Blooming rabbitbrush becomes a butterfly magnet, drawing painted ladies, red admirals, and sulphurs to feed on warm afternoons.
- In the high valleys the first frost can arrive by late month — be ready to cover tomatoes and squash on clear, calm nights.
August 20–26
- Alpine breeders fatten near the last snowfields as Clark's nutcrackers cache pine seed and the first hawks gather along the ridges.
- The highest, driest aspen stands show the first golden flecks that foretell the September blaze across the mountain slopes.
- Monarchs from the valley milkweed begin staging for the long drift south as the new mourning-cloak brood feeds up for hibernation.
August 27 – September 2
- Bull elk begin bugling in the mountains by month's end, the rut opening in Yellowstone, Grand Teton, and the high parks.
- The Milky Way still arches overhead through Cygnus as the autumn Great Square of Pegasus climbs the eastern sky.
- The harvest peaks with onions and garlic curing, the first winter squash, and the cool nights sweetening the fall greens.
Birds This Month
August turns Wyoming's birding toward migration as breeding winds down. Shorebirds funnel through the drying mudflats of Seedskadee NWR, Ocean Lake, and the reservoir margins — least, Baird's, and western sandpipers, long-billed dowitchers, greater and lesser yellowlegs, Wilson's phalaropes, and American avocets staging in numbers. Swallows mass on wires, common nighthawks stream south at dusk, and the first warblers and flycatchers trickle through the cottonwoods in fall plumage.
In the high country the alpine breeders fatten before leaving — American pipits, white-crowned sparrows, and gray-crowned rosy-finches around the last snowfields — and Clark's nutcrackers begin caching the new crop of whitebark and limber pine seeds. Broad-tailed and rufous hummingbirds work the late paintbrush and gilia on their way south. Raptors start to move along the ridges — Swainson's hawks gathering, Golden Eagles on the thermals — and the sage holds family groups of Greater Sage-Grouse and young pronghorn bands feeding across the flats.
This month's tip: work reservoir edges and wet meadows for staging shorebirds, best at dawn before the wind, and watch the late-month evenings for nighthawk and swallow movements — fall migration is quietly underway even as summer holds.
What's Blooming
August carries Wyoming's bloom into late summer, holding longest in the high country and the late-season flats. The alpine and subalpine meadows of the Tetons, Wind Rivers, and Beartooths keep flowering into the month — late Indian paintbrush, fringed and mountain gentian, elephant's head, aster, fireweed blazing pink up the burned and open slopes, and arnica and goldenrod. Lower down the sagebrush flats and roadsides turn to the late-summer palette — rabbitbrush just beginning its gold, blanketflower, wild sunflower, gumweed, aster, and the silvery plumes of curing grasses. Rocky Mountain bee plant and the last wild blue flax hold along disturbed ground. Fireweed's seed cotton and the seed heads of the spring flowers signal the turn, but a warm August day in a Teton meadow still offers a remarkable spread of late bloom.
Garden This Month
August is peak harvest in Wyoming's gardens, and it is the month frost begins to loom. The cool mountain nights keep greens, brassicas, and roots crisp and sweet, and the summer crops — beans, summer squash, cucumbers, the first ripe tomatoes in the warmer basins, potatoes, carrots, beets, and cabbage — come in fast. Pick daily to keep plants bearing, and keep watering deeply, as the hot, dry, windy basin days still pull moisture hard even as the nights cool.
The short season now turns toward its close. In the high valleys the first frost can strike by late August, so watch clear, calm nights and keep row cover ready to protect tomatoes, peppers, and squash and stretch the harvest. Pull and cure onions and garlic as their tops fall, lift the first potatoes, and sow one last quick succession of spinach, lettuce, and radishes that will mature in the cool of September. Begin saving seed from the best plants and planning the fall cleanup.
Zone 3b (Jackson Hole, high valleys): the first frost can arrive by late August here, so watch the forecast closely — be ready to cover tomatoes and squash on clear, calm nights, and harvest the heat-lovers before a hard freeze. Keep cutting the cool-season crops that the cold nights keep sweet.
Zone 4a (high basins, Lander, Cody): the garden is at peak harvest; keep watering deeply, pick daily to keep plants producing, and start covering for the first early-September frosts. Sow a last quick crop of spinach and radishes for fall.
What's at the Farmers Market
August is the fullest market month in Wyoming, with the short, intense harvest at its peak across Jackson, Cheyenne, Laramie, Sheridan, Cody, and the valleys. The tables overflow: tomatoes from the warmer basins, sweet corn, summer squash, cucumbers, green beans, potatoes, carrots, beets, cabbage, broccoli, peppers, and onions, plus a deep run of raspberries and the first fall greens sweetened by the cool nights. The state's grass-fed beef, lamb, and bison hold their place from local ranches.
This is also when fresh Wyoming honey flows fully from the alfalfa and clover crop, alongside cut flowers, fresh herbs, and eggs. Eat the berries and corn the day you buy them, refrigerate berries unwashed and keep corn in its husk, and store potatoes, onions, and roots in a cool, dark, dry spot for keeping.
Night Sky This Month
August is one of Wyoming's three finest months for the night sky, with warm nights, the Milky Way overhead, and the year's best meteor shower. The Red Desert and southwest basins, and the high backcountry of Yellowstone and Grand Teton, are premier dark-sky destinations, and summer star parties gather in the cool high valleys under skies as dark as any in the Lower 48.
The Milky Way arches from Sagittarius and Scorpius low in the south straight overhead through Cygnus, blazing with star clouds, dark rifts, and the nebulae and clusters of the galactic core — a sight that alone justifies the drive to a dark basin. The Summer Triangle rides high, and the Perseid meteor shower peaks around August 12, often delivering dozens of meteors an hour from these dark skies — find an open horizon, lie back after midnight, and watch the radiant in Perseus climb the northeast.
Exact planet positions and this year's Perseid timing and moon phase shift year to year — the printable Wyoming night-sky guide lists the dates and the darkest viewing sites near you.
Butterflies & Pollinators
August keeps Wyoming's butterflies abundant, with a late-season character. The sagebrush flats, roadsides, and gardens fill with nectaring adults on the late bloom — painted ladies and West Coast ladies, red admirals, Milbert's tortoiseshells, mourning cloaks of the new summer brood, clouded and orange sulphurs, a continuing run of blues and coppers, the large fritillaries still flying over the meadows, and a strong showing of skippers on the grasses. Western tiger and two-tailed swallowtails patrol the river bottoms, and monarchs from valley milkweed begin staging for the long drift south. In the high country the alpine season is closing — the last parnassians, alpine fritillaries, and tundra satyrs fly into early August before the cold shuts them down. Rabbitbrush coming into gold, fireweed, aster, and goldenrod become the key late-summer nectar; watch them through warm afternoons for the season's last great gathering of butterflies.
What to plant for them is in the Wyoming native plants guide
Trees This Month
August holds Wyoming's trees in mature, late-summer green, with the first hints of the turn. In the river bottoms the plains cottonwoods show occasional yellowing leaves in the dry heat, and along the irrigated valleys they cast their deepest shade over the Green, Snake, and North Platte. On the mountain slopes the quaking aspens stay full and green but begin, in the highest and driest stands, to show the first golden flecks that foretell the September blaze.
The conifers ripen their cones. Lodgepole pine across the Yellowstone plateau holds its closed serotinous cones, Douglas-fir sheds winged seed, and at treeline the whitebark and limber pines set the fat, seed-rich cones that Clark's nutcrackers begin frantically harvesting and caching for winter — a keystone interaction of the high Rockies. The dry foothill Rocky Mountain junipers color their berry-like cones blue, and along the streams the willows and alders stay green. Watch the fruiting chokecherry and serviceberry thickets for bears, waxwings, and robins stripping the ripe fruit.
Weather & Daylight
Across Wyoming, a typical August day averages a high near 80°F and a low near 49°F, with about 1.0 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
Still solidly hot with highs around 80, muggy nights near 50, and rainfall staying light and infrequent.
| Average high | 80°F |
|---|---|
| Average low | 49°F |
| Precipitation | 1.0 in |
| Sunrise (mid-month) | 6:15 MT |
| Sunset (mid-month) | 20:13 MT |
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 (MT).
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One short note when Wyoming's next month turns — what's arriving, blooming, and worth a night outside.
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Same month elsewhere: August in Alabama · August in Arizona · August in Arkansas