May is the crescendo of Oregon birding — Malheur's migration peaks, the dawn chorus fills the valley, and Cascade snowmelt feeds roaring waterfalls. Rhododendrons bloom on the coast, the Gorge wildflowers peak, and the garden finally turns to summer crops.
Week by week in May
April 30 – May 6
- Malheur's spring chorus is still in full voice from April's migration peak, when birders gathered for the Harney County Migratory Bird Festival in mid-April.
- The Eta Aquariid shower, debris of Halley's Comet, peaks in early May, best in the pre-dawn southeast from a dark high-desert site.
- Pacific rhododendron opens along the Coast Range, building toward its pink peak at Florence — celebrated at the town's Rhododendron Festival on the third full weekend of May.
May 7–13
- The seabird colonies at Yaquina Head and Three Arch Rocks crowd with nesting common murres, tufted puffins, and pelagic cormorants.
- The Columbia Gorge wildflower show peaks with balsamroot, lupine, paintbrush, and the Gorge endemics at Rowena and Tom McCall.
- Western tiger and pale swallowtails are abundant along streams and gardens, and Oregon swallowtails sail the eastside river canyons.
May 14–20
- After the valley's average mid-May last frost, set out tomatoes, peppers, squash, and basil, and direct-sow beans and corn into warm soil.
- The first sweet Hood and Oregon strawberries ripen — intensely sweet and fragile — alongside peak asparagus and the season's first morels.
- Vaux's swifts swirl into chimney roosts at dusk, and western tanagers and lazuli buntings fill the dawn chorus.
May 21–27
- California tortoiseshells may mass and stream over the Cascade passes in irruption years, a remarkable Oregon spectacle.
- The lowest Cascade meadows begin as the snow recedes — avalanche lilies and lupine at Mount Hood and the Three Sisters trailheads.
- Pacific madrone hangs clusters of white urn-shaped flowers on the coast and southwest hills as it peels its bark to cinnamon.
May 28 – June 3
- The breeding season is in full song; on the coast, Haystack Rock and Three Arch Rocks bustle with murres, puffins, and oystercatchers feeding chicks.
- Oregon strawberries peak and the first raspberries and boysenberries arrive, with Hood River cherries beginning.
- Mulch beds heavily against the coming dry summer and establish deep, consistent irrigation as the rains taper off.
Birds This Month
May is Oregon's birding crescendo. Malheur National Wildlife Refuge hits its legendary peak — the desert oases drip with migrant warblers, vireos, tanagers, and flycatchers, while the marshes teem with breeding white-faced ibis, black-necked stilts, American avocets, Wilson's phalaropes, trumpeter swans, and Franklin's gulls. Birders gathered from across the continent for April's Harney County Migratory Bird Festival, and the refuge is still ringing with the season's arrivals.
Statewide the breeding season is in full song: western tanagers, black-headed grosbeaks, lazuli buntings, Bullock's orioles, Swainson's thrushes, and a dozen warblers fill the dawn chorus, and the western meadowlark (state bird) sings across the grasslands. On the coast, the seabird colonies on Three Arch Rocks and Yaquina Head are crowded with nesting common murres, tufted puffins, pelagic cormorants, and pigeon guillemots. Vaux's swifts swirl into chimney roosts at dusk.
What's Blooming
May is a riot of bloom across Oregon's many habitats. On the coast and in the Coast Range, the Pacific rhododendron reaches its pink peak — Florence's Rhododendron Festival celebrates it — alongside flowering salmonberry, red huckleberry, and salal. The Willamette Valley prairies finish their camas and shift to Kincaid's lupine, tough-leaved iris, checkermallow, and blue-eyed grass.
The Columbia Gorge wildflower show peaks: balsamroot, lupine, paintbrush, desert parsley, and the Gorge endemics at Rowena and the Tom McCall Preserve. In the forest, Pacific dogwood, vanilla leaf, inside-out flower, and columbine bloom, and the state flower Oregon grape finishes. East of the Cascades, the desert flowers — bitterroot, phlox, larkspur, and balsamroot — peak on the warming sage slopes, and the lowest Cascade meadows begin as the snow recedes.
Garden This Month
May is when the western Oregon garden turns to summer. After the valley's average last frost passes in mid-May, set out the warm-season crops — tomatoes, peppers, eggplant, squash, cucumbers, melons, and basil — and direct-sow beans, corn, and summer squash into soil that has finally warmed. Keep succession-sowing lettuce, carrots, and beets for continuous harvest, and plant out dahlias and warm annual flowers.
Stake and cage tomatoes, mulch beds against the coming dry summer, and side-dress heavy feeders. Slugs still threaten new transplants, so stay vigilant. Harvest the early rewards — asparagus, peas, radishes, lettuce, spinach, and the first strawberries. East of the Cascades, the short high-desert season is opening, but hold warm crops under protection — Bend's last frost can come into June — and sow the hardiest cool crops directly now.
Zone 6b (Bend & high desert): frost still threatens into June; sow hardy crops and harden warm-season starts, but keep tomatoes and squash protected under wall-o-water or cloche until nights reliably stay above freezing.
Zone 8a (Willamette Valley): after the average last frost passes mid-month, set out tomatoes, peppers, squash, cucumbers, and basil, and direct-sow beans and corn into warm soil. Keep row cover for any late cold snap.
Zone 8b (southwest valleys & coast): warm crops go out freely now; succession-sow beans and greens, and plant out melons and peppers in the warmest beds. Cool coastal sites favor greens and brassicas over heat-lovers.
What's at the Farmers Market
May markets burst into spring abundance. The first Hood and Oregon strawberries ripen — the local June-bearers are intensely sweet and fragile, dramatically better than shipped fruit — alongside peak asparagus, rhubarb, spring greens, peas, radishes, green garlic, spring onions, and the first salad turnips. Foraged morels from the Cascades and fiddleheads reach their peak. Cook fiddleheads thoroughly before eating — boil 15 minutes or steam 10–12; never raw.
Markets are fully open across the state — Portland, Corvallis, Hillsdale, Beaverton, Eugene — and stalls overflow with vegetable and flower starts, bedding plants, and bouquets of tulips, peonies, and lilacs. Coastal towns land spring chinook and the last Dungeness crab. Choose strawberries fully red and fragrant and eat them within a day, since they won't sweeten after picking; refrigerate them unwashed and keep tender greens cool and use them quickly. One of the best market months of the Oregon year.
Night Sky This Month
May's mild, increasingly clear nights are ideal for Oregon's high-desert dark-sky sites as summer approaches. Pine Mountain Observatory east of Bend opens for regular public weekend viewing, the Oregon Outback International Dark Sky Sanctuary near Lakeview and Prineville Reservoir State Park deliver pristine skies, and the Cascade lakes country and Steens open as the snow leaves. Oregon Star Party planning peaks for the late-summer gathering near Indian Trail Spring.
The spring sky is at its best: Leo and Virgo ride high with their galaxy fields, orange Arcturus blazes overhead (follow the Big Dipper's handle arc to it and on to blue-white Spica), and the great globular cluster M13 in Hercules climbs the east. By late evening the first Summer Triangle stars rise. The Eta Aquariid shower, debris of Halley's Comet, peaks in early May, best in the pre-dawn southeast. The printable Oregon night-sky guide gives this year's planet positions and dark-sky dates.
Butterflies & Pollinators
May is a peak butterfly month statewide. West of the Cascades, western tiger swallowtails and pale swallowtails are abundant along streams and gardens, anise swallowtails patrol hilltops, and spring azures, echo blues, silvery blues, and the first woodland skippers flit through meadows. The endangered Fender's blue flies in its few Willamette Valley prairie sites on its host Kincaid's lupine — a conservation highlight.
The Columbia Gorge and warming eastside come alive: Oregon swallowtails (the state insect) sail the Snake and Columbia canyons, juniper hairstreaks, sagebrush coppers, and many blues work the desert flowers, and California tortoiseshells may mass and stream over the Cascade passes in irruption years. Sara orangetips, painted ladies, and cabbage whites are everywhere. The Cascade lower meadows wake as the snow melts. Plant nectar plants and native hosts to fuel the building summer broods.
Trees This Month
May leafs out the last of Oregon's trees and shifts the bloom to the broadleaf canopy. Oregon white oak is fully out on the valley savanna, and the forest's Pacific dogwood opens its showy white-bracted flowers among the firs. On the coast and southwest hills, the Pacific madrone hangs clusters of white urn-shaped flowers, and the California black oak and chinquapin flush new growth.
The conifers push their brightest new growth now — the state tree, Douglas-fir, with reddish pollen cones and lime-green tips, alongside grand fir, noble fir, western hemlock, and Sitka spruce. The flowering shifts to the smaller trees and shrubs: cascara, oceanspray, red elderberry, and fragrant black locust in the towns. East of the Cascades, the ponderosa pine candles out, the western larch is soft green, and the quaking aspen, serviceberry, and chokecherry bloom and leaf along the desert streams.
Weather & Daylight
Across Oregon, a typical May day averages a high near 64°F and a low near 39°F, with about 2.4 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
Pleasantly warm afternoons in the low 60s with cool nights in the high 30s, and rain showers becoming lighter and less frequent.
| Average high | 64°F |
|---|---|
| Average low | 39°F |
| Precipitation | 2.4 in |
| Sunrise (mid-month) | 5:41 PT |
| Sunset (mid-month) | 20:27 PT |
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 (PT).
Next month's version of this page, by email
One short note when Oregon's next month turns — what's arriving, blooming, and worth a night outside.
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Same month elsewhere: May in Pennsylvania · May in Rhode Island · May in South Carolina