May is the lush green peak of the Oklahoma year — Indian blanket sets the roadsides ablaze, Mississippi kites wheel over the towns, and the prairies reach their fullest bloom. It is also the climax of the state's severe-weather season.
Week by week in May
April 30 – May 6
- Indian blanket sets roadsides ablaze statewide beside golden coreopsis, the famous Oklahoma wildflower show.
- Scissor-tailed Flycatchers perform their tumbling 'sky dance' courtship flights over the open prairies.
- The Eta Aquariid meteors, debris from Halley's Comet, favor the predawn east low on the southern horizon.
- Sow heat-lovers now: okra, southern peas, sweet potato slips, and melons as the soil warms into the seventies.
May 7–13
- Painted and indigo buntings, blue grosbeaks, and Bell's vireos sing from brushy prairie and roadside statewide.
- Butterfly milkweed flames orange and purple coneflower opens on the tallgrass and mixedgrass prairies.
- Swallowtails are at their showiest and the blooming Indian blanket roadsides draw nectaring clouds of butterflies.
- Strawberries, new potatoes, spring carrots, and the last sweet spring greens fill the late-spring tables.
May 14–20
- Grassland specialists settle in: grasshopper and Henslow's sparrows, upland sandpipers, and singing meadowlarks.
- The Wichita Mountains granite slopes bloom with paintbrush, blanketflower, and prickly pear in yellow flower.
- Pull bolting cool-season greens, mulch heavily for the heat, and stake tomatoes; peak tornado and hail season.
- Cottonwoods release drifting cottony seed along the prairie rivers as catalpas open showy white flowers.
May 21–27
- At Salt Plains the Snowy Plovers, least terns, and avocets are nesting on the open salt flats.
- The declining regal fritillary begins flying in the best tallgrass remnants like the Tallgrass Prairie Preserve.
- Black-eyed Susan, spiderwort, and prairie clover open among the rising grasses across the tallgrass prairie.
- The Summer Triangle's Vega rises in the east as the spring sky's Arcturus and Spica ride high after dark.
May 28 – June 3
- Summer tanagers, blue grosbeaks, and painted buntings fill the Wichita Mountains and Cross Timbers woodlands.
- Pecans hang heavy with drooping catkins in the bottomland groves, pollinating for the fall nut crop.
- The first squash and cucumbers join strawberries and asparagus as the season swings toward summer.
- Side-dress corn and tomatoes, scout for squash bugs and hornworms, and keep the heat-lovers well watered.
Birds This Month
May is peak breeding season and the tail of migration in Oklahoma. Scissor-tailed Flycatchers are established on every prairie fence wire, performing their tumbling 'sky dance' courtship flights, and Mississippi kites wheel in elegant flocks over towns, parks, and river bottoms, especially across the southern and central counties. Painted and indigo buntings, dickcissels, orchard orioles, and Bell's vireos sing from brushy prairie and roadside, the full chorus of the Oklahoma summer.
The last migrants pass through the eastern woods in early May — a final wave of warblers, rose-breasted grosbeaks, and flycatchers — while grassland specialists settle on territory: grasshopper sparrows, Henslow's sparrows in the tallgrass, upland sandpipers on the prairies, and Western and Eastern meadowlarks both singing. At Salt Plains, the Snowy Plovers, American avocets, and least terns are nesting on the open salt flats.
The Wichita Mountains and Cross Timbers fill with summer tanagers, blue grosbeaks, and painted buntings. Resident birds are deep into nesting, with fledglings appearing by late month.
This month's tip: May is the best month to soak in the full prairie-bird community at once — drive a grassland route at dawn for scissor-tails, dickcissels, meadowlarks, and upland sandpipers all singing together, the signature Oklahoma soundscape.
What's Blooming
May is the explosion of Oklahoma's prairie wildflowers and the month the state is most famous for. Indian blanket (firewheel) — the state wildflower — blankets roadsides, pastures, and prairies statewide in sheets of red-and-yellow pinwheels, often beside drifts of golden plains coreopsis, purple winecup, white prairie larkspur, and the magenta of purple poppy mallow. The roadsides of central and southern Oklahoma become natural wildflower gardens.
The tallgrass and mixedgrass prairies are at their fullest: black-eyed Susan, butterfly milkweed in brilliant orange, prairie clover, spiderwort, and the first purple coneflower open among the rising grasses. The granite slopes of the Wichita Mountains bloom with paintbrush, blanketflower, and prickly pear cactus coming into yellow flower.
Where to see it: almost any rural roadside in central and southern Oklahoma puts on a show now, but the Tallgrass Prairie Preserve and the Wichita Mountains NWR show the wildflowers in their full native prairie setting, with bison grazing among the blooms. This is the peak month to photograph the Indian blanket the state is known for.
Garden This Month
May is full planting and fast growth in the Oklahoma garden. The warm-season crops set out in April are taking off, and now is the time to add the true heat-lovers that resent cool soil: okra, southern (field) peas, sweet potato slips, cantaloupe, watermelon, and a second succession of green beans and sweet corn. These thrive as the soil warms into the seventies and reward Oklahoma's long, hot summer. Pull the cool-season greens, lettuce, and spinach as they bolt in the rising heat, and harvest the last spring peas.
The work now shifts to maintenance for the coming heat. Mulch everything heavily to conserve the spring moisture before the summer dries down, set up an efficient watering plan, and stake and cage tomatoes before they sprawl. Scout for the season's first pests — squash bugs, hornworms, and aphids — and stay weather-ready, because May is the absolute peak of Oklahoma's tornado and large-hail season, and a single storm can flatten a garden, so know where your covers and shelter are. Side-dress heavy feeders like corn and tomatoes as they grow.
Zone 6b (panhandle and far northwest): with the late frost finally past, the warm-season garden goes in fully now. Set out tomatoes, peppers, and squash, direct-sow beans, corn, and melons, and begin steady irrigation — the High Plains wind and dry heat stress new plantings fast.
Zone 7a (central and northeastern Oklahoma): the warm-season garden is fully planted and growing hard. Sow heat-lovers now — okra, southern peas, sweet potatoes, and a second round of beans and corn — mulch heavily to hold moisture, and pull the bolting cool-season greens.
What's at the Farmers Market
May markets bridge spring and summer across Oklahoma. The last of the cool-season crops — sweet spring lettuce, spinach, sugar snap peas, green onions, radishes, kohlrabi, and bunches of asparagus — are at their finest before the heat ends them, and the first new potatoes, spring carrots, and beets arrive. The first strawberries from Oklahoma growers are a highlight of the month.
Tables also fill with spring onions, garlic scapes, fresh herbs, and the season's last transplants for late planters. Cut flowers — peonies, snapdragons, and the first zinnias — brighten the stands, and farm eggs and local honey remain steady. By late May the very first squash and cucumbers may appear from early or tunnel growers.
For selection and storage: choose strawberries that are fully red, fragrant, and free of soft spots, and refrigerate them unwashed in a single layer, using within a day or two. Keep new potatoes cool and dark but not refrigerated, store spring greens and peas crisp and dry in the refrigerator for prompt use, and stand asparagus and herbs upright in a little water to keep them fresh.
Night Sky This Month
May offers warm, comfortable nights for Oklahoma stargazing, though the frequent late-spring storms and humidity can haze the sky. The dark Black Mesa country and Black Mesa State Park in the panhandle stay the state's premier dark site, and the open Wichita Mountains remain an excellent, accessible escape from city light for central Oklahoma; astronomy clubs run public observing nights as the weather cooperates.
The spring sky is in full display. The Big Dipper rides high overhead, and the 'arc to Arcturus, spike to Spica' line leads from its handle to bright orange Arcturus in Boötes and on to blue-white Spica in Virgo. Leo still stands in the west, and rising in the east are the summer harbingers — the keystone of Hercules and the bright star Vega, herald of the coming Summer Triangle. The faint summer Milky Way begins to clear the eastern horizon late at night.
The Eta Aquariid meteor shower, debris from Halley's Comet, peaks in early May but favors the predawn hours and southern latitudes; Oklahoma's southern position gives a modest view low in the east before dawn. For this year's exact peak, moon phase, and planet positions from your latitude, see the printable Oklahoma night-sky guide.
Butterflies & Pollinators
May is a high-diversity butterfly month across Oklahoma as summer broods build. The swallowtails are at their showiest — eastern tiger, black, giant, pipevine, and the striped zebra swallowtail where pawpaw grows in the east — sailing through woodland edges and nectaring on the blooming roadsides. Prairies and gardens swarm with pearl crescents, orange and clouded sulphurs, variegated fritillaries, painted and American ladies, and the eyespotted common buckeye.
The prairie wildflower peak means abundant nectar, and the Indian blanket and coreopsis roadsides draw clouds of butterflies and skippers. The big prairie specialist, the declining regal fritillary, begins flying in the best tallgrass remnants late in the month. The spring monarch generation has largely moved on north, but locally raised monarchs from Oklahoma milkweed are emerging. Watch for the bright little gray and juniper hairstreaks and many fast-flying skippers on the flowers.
To make the most of the season: May is one of the best butterfly-watching months of the Oklahoma year — visit a blooming prairie roadside or the Wichita Mountains on a warm, calm morning. Keep your garden nectar coming and leave host plants like milkweed, pawpaw, and passionflower undisturbed to fuel the summer broods.
What to plant for them is in the Oklahoma native plants guide
Trees This Month
May fills the Oklahoma woods with deep summer green and a flush of tree bloom. The southern catalpa opens showy clusters of white, frilly flowers, the native black locust drips fragrant white spikes, and in towns and bottoms the chinaberry and the magnificent native American smoketree of the limestone hills flower. The bottomland pecans — a signature Oklahoma tree — hang heavy with drooping catkins as they pollinate for the fall nut crop.
The hardwoods are now in full, dense leaf. The Cross Timbers post oaks and blackjack oaks wear a complete canopy, the cottonwoods release their drifting cottony seed along the prairie rivers, and the bald cypress is fully feathered green over the southeastern swamps. The eastern red cedars set their tiny green developing cones. Along streams, the black walnuts and green ash finish leafing, completing the canopy. The woodland floor, now deeply shaded, has gone quiet as the spring ephemerals set seed and retreat underground for another year.
The Oklahoma native plants guide covers what grows with them
Weather & Daylight
Across Oklahoma, a typical May day averages a high near 80°F and a low near 57°F, with about 4.9 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
Genuinely warm now, near 80F afternoons and mild 57F nights, with heavy spring showers reaching their peak for the year.
| Average high | 80°F |
|---|---|
| Average low | 57°F |
| Precipitation | 4.9 in |
| Sunrise (mid-month) | 6:24 CT |
| Sunset (mid-month) | 20:25 CT |
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 (CT).
Next month's version of this page, by email
One short note when Oklahoma's next month turns — what's arriving, blooming, and worth a night outside.
Go deeper with the Oklahoma guides
The complete Oklahoma birding, native-plant, and night-sky references — or the whole year, week by week, in one book.
Same month elsewhere: May in Oregon · May in Pennsylvania · May in Rhode Island