August is the deep monsoon — the green desert at its lushest, the southeastern canyons at their hummingbird and butterfly peak, and the green chile harvest in full swing. The afternoon storms keep building, and the high country glows.
Week by week in August
July 30 – August 5
- The sky-island hummingbird show climbs toward its August peak as migrant species pour through the canyons.
- Bordered Patch, checkerspots, and dozens of skippers swarm the monsoon-fed grasslands of the southeast.
- The green desert is spangled with yellow Arizona poppy and summer sunflowers after the storms.
- Set out fall tomato and pepper transplants now so they fruit in the mild, frost-free desert autumn.
August 6–12
- Up to fifteen hummingbird species swarm the Madera and Ramsey Canyon feeders at the August birding climax.
- The Perseid meteor shower peaks around August 12, one of the year's best on a clear monsoon-break night.
- The southeastern canyons reach the richest butterfly diversity in the country with Mexican strays crossing the border.
- Hatch-style green chiles are roasted fragrantly at the markets in the late-summer harvest.
August 13–19
- The high-country meadows of Flagstaff's peaks blaze with scarlet penstemon, paintbrush, and golden sunflowers.
- Fall shorebird migration peaks at desert ponds with Wilson's Phalaropes and Western Sandpipers.
- Start the first cool-season seedlings indoors for September transplanting into the low-desert winter garden.
- The plumped saguaro stands fat and green as the monsoon keeps the desert at its most verdant.
August 20–26
- Queens, monarchs, and Variegated Fritillaries work the blooming milkweed in the lush monsoon desert.
- Southbound flycatchers, warblers, and orioles begin trickling through the riparian corridors.
- Sweet corn, eggplant, and the first fall winter squash join the green chiles at the stalls.
- Barrel cacti ring their crowns with orange flowers amid the green monsoon desert.
August 27 – September 2
- Fall hawk migration builds over the Grand Canyon's Yaki Point and the southeastern ridges.
- Desert broom and seepwillow begin their masses of butterfly-thronged yellow flowers in the washes.
- The first quaking aspens flush gold on the highest groves of the San Francisco Peaks.
- The great low-desert fall planting begins as the heat eases — set out broccoli, lettuce, and greens.
Birds This Month
August is one of Arizona's premier birding months, thanks to the monsoon and the start of fall migration. The southeastern sky islands reach their hummingbird climax — the feeders at Madera Canyon, Ramsey Canyon, and the Chiricahuas swarm with up to fifteen species as migrant Rufous, Calliope, and Broad-tailed Hummingbirds pour through to join the breeding Magnificent, Blue-throated, Broad-billed, and Violet-crowned. The monsoon brings Mexican rarities north, and this is the famous month when birders gather for the August hummingbird spectacle.
Fall shorebird migration peaks at desert ponds, sewage lagoons, and the Salt and Colorado rivers, where Wilson's Phalaropes, Western and Least Sandpipers, and Black-necked Stilts gather. The green grasslands of the southeast still ring with Botteri's and Cassin's Sparrows, and Montezuma and Scaled Quail move with their broods through the lush grass.
In the desert, the second monsoon nesting wave continues, and southbound migrant flycatchers, warblers, and orioles begin trickling through the riparian corridors. The high country's Western Tanagers and warblers prepare to move south.
This month's tip: the southeastern canyons in August are a global birding event — spend a morning at the hummingbird feeders for the year's greatest diversity, then bird a desert pond for migrant shorebirds.
What's Blooming
August is the lush heart of the monsoon bloom, and the desert is greener and more flowery now than at almost any other time. The Arizona poppy spreads yellow across the desert floor, joined by summer sunflowers, devil's claw, spiderling, morning glory, desert zinnia, and roadside sunflowers. The barrel cacti bloom in rings of orange and yellow at their crowns, and the desert washes are green and humming with pollinators.
The high country is at its wildflower peak. The Mogollon Rim and the meadows of the San Francisco Peaks blaze with scarlet penstemon, Indian paintbrush, lupine, columbine, sunflowers, asters, goldenrod, and acres of golden composites — a magnificent mountain bloom fueled by the summer rains. The aspen meadows and forest openings are at their most colorful.
Where to look: the green desert around Tucson and Phoenix is spangled with Arizona poppy and summer sunflowers now — drive a desert road after a storm. For the grandest show, head to Flagstaff's peaks and the Mogollon Rim, where the high meadows are a sea of penstemon, paintbrush, and golden sunflowers.
Garden This Month
August is the pivot of the desert gardening year — the most important fall-planting month in the low desert. The fall tomato and pepper transplants started in July go in the ground now, timed so they set fruit in the mild, frost-free autumn when day temperatures finally drop back below 100°F; this fall crop is often more reliable than the spring one in the desert. Direct-sow more squash, beans, cucumbers, and melons under the monsoon, and late in the month start the first cool-season seedlings — broccoli, cauliflower, and cabbage — indoors for September transplanting.
The monsoon rains help, but bring fungal pressure in the humidity, so water in the morning, ensure drainage, and space plants for airflow. Give citrus its late-summer feeding. In the transitional and high country, August begins the turn toward fall — Prescott and the Verde Valley harvest summer crops while sowing fall greens, and Flagstaff gardeners race the first possible September frost. The desert's second growing season is just beginning as the high country's winds down.
Zone 6b (Flagstaff and the high country): the short season is winding down — harvest steadily, as the first frost can come as early as September on the peaks. Sow quick cool-season greens, and start protecting tender plants on clear nights when high-country temperatures drop.
Zone 7a (Prescott, Verde Valley): still in full summer harvest — keep tomatoes, peppers, squash, and beans producing, and begin sowing fall cool-season crops late in the month as the nights start to lengthen. Watch for the first hint of the season's turn.
Zone 9b (Phoenix, Tucson, lower valleys): the critical fall-planting month — set out the fall tomato and pepper transplants now (started in July) so they fruit in the mild autumn, and direct-sow squash, beans, and cucumbers under the monsoon. Late in the month, start the first cool-season seedlings indoors. Ease watering after storms and watch for fungal issues in the humidity.
What's at the Farmers Market
August markets are at a summer high across Arizona's elevations. The desert and valley fields bring melons still at their peak, tomatoes, summer squash, zucchini, cucumbers, eggplant, okra, green beans, and the headline crop — Hatch-style green chiles, roasted fragrantly at the markets in the late-summer harvest. Abundant basil, sweet corn, and the first fall winter squash appear.
The high-country stalls around Flagstaff, Prescott, and the Verde Valley add cool-grown sweet corn, greens, beans, and early apples. Choose firm glossy chiles, heavy fragrant melons, and corn with green tight husks and plump kernels; pick tomatoes that are fragrant and give slightly.
For selection and storage: green chile season is the signature of August — buy a bag, have it roasted, and freeze what you won't use soon. Keep tomatoes at room temperature, store squash and beans in the crisper, and refrigerate sweet corn promptly to hold its sweetness.
Night Sky This Month
August stargazing in Arizona is a dance with the monsoon, but the clear windows between storms deliver the summer Milky Way at its most spectacular, and the famous Perseid meteor shower peaks mid-month. The high dark country — Flagstaff, the Grand Canyon, and the Mogollon Rim — and southern sites like Kitt Peak and Oracle State Park all offer superb skies when the clouds break. Watch the afternoon and evening thunderheads for dramatic lightning displays as a bonus.
The Perseid meteor shower peaks around August 12, one of the year's best and most reliable showers, throwing dozens of bright meteors an hour from a dark site after midnight — a clear monsoon-break night under Arizona's dark skies makes for a memorable show. Overhead, the summer Milky Way blazes from Cygnus down through Sagittarius and the galactic center in the south, with the Summer Triangle riding high.
For the Perseids, find a dark site away from city lights and watch the sky after midnight. For this year's exact peak timing, moon phase, and planet positions, see the printable Arizona night-sky guide.
Butterflies & Pollinators
August is the absolute peak of Arizona's butterfly year, especially in the famous southeast, where the monsoon-fed canyons and grasslands host the richest butterfly diversity in the United States. The desert and mountains teem with species: Queens and monarchs, Two-tailed and Pipevine Swallowtails, Gulf and Variegated Fritillaries, Bordered Patch, Arizona Sister, and clouds of sulphurs, whites, blues, and hairstreaks over the blooming summer flowers.
The sky-island canyons of the Huachucas and Chiricahuas draw butterfly watchers from across the country, with metalmarks, checkerspots, dozens of skippers, and Mexican strays that cross the border with the rains — a single good day can yield well over a hundred species. Empress Leilia works the desert hackberry, and the grasslands swarm with skippers and sulphurs.
To help them: the monsoon bloom is the year's great nectar feast — leave the summer wildflowers and milkweed standing, keep garden lantana and zinnia going, and provide a damp puddling spot. Plant native milkweed, passionvine, and pipevine, and absolutely avoid spraying during this peak of butterfly abundance.
What to plant for them is in the Arizona native plants guide
Trees This Month
August's monsoon keeps Arizona's trees lush and growing. The saguaro, plumped with stored water in its pleated trunk, stands fat and green, and the palo verde (the state tree), mesquite, and ironwood carry full summer canopies. Desert willow blooms on along the washes, and the riparian cottonwoods and willows, recharged by the flowing washes, shade the green desert streams. The desert is at its most verdant of the year.
The high country thrives in the cool, wet summer. The ponderosa pine forests of the Mogollon Rim and the aspen, Douglas-fir, white fir, and Engelmann spruce of the San Francisco Peaks are deep green and growing fast on the monsoon moisture. In the sky-island canyons, the Arizona sycamores, bigtooth maples, and Arizona walnuts shade the cool streams. The summer rains have erased the spring fire danger, and from saguaro to spruce the state is green and alive — a brief, lush peak before the autumn turn.
Weather & Daylight
Across Arizona, a typical August day averages a high near 93°F and a low near 66°F, with about 1.9 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
Still sweltering in the low 90s, with the year's heaviest, stickiest rains rolling through most afternoons.
| Average high | 93°F |
|---|---|
| Average low | 66°F |
| Precipitation | 1.9 in |
| Sunrise (mid-month) | 5:48 MT |
| Sunset (mid-month) | 19:14 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 Arizona's next month turns — what's arriving, blooming, and worth a night outside.
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Same month elsewhere: August in Arkansas · August in California · August in Colorado