North Dakota Nature Guide: May 2026
Data updated: August 2026Sources & method · Corrections
May is peak migration and the start of the prairie nesting season — one of the two best birding months in North Dakota. Grassland songbirds pour back onto the native sod, the potholes ring with breeding ducks, and the last frost finally releases the gardens of the southern valleys.
Week by week in May
April 30 – May 6
- Grassland specialties return to the mixedgrass prairie — the skylarking Sprague's pipit and tinkling Baird's sparrow sing in the calm dawn air.
- Prairie smoke opens across dry mixedgrass prairie, and chokecherry and juneberry hang white racemes in the shelterbelts and draws.
- Direct-sow peas, lettuce, beets, carrots, and potatoes; harden off tomatoes and peppers but keep frost cloth ready for late freezes.
May 7–13
- Shorebird migration peaks on pothole mudflats — marbled godwits, avocets, Wilson's phalaropes, and flocks of peeps work the edges.
- Monarchs reach the southern counties, and Canadian tiger swallowtails drift through the wooded draws as the season's emergences build.
- The Big Dipper rides high overhead, its handle arcing to brilliant orange Arcturus; many astronomy clubs hold spring star parties now.
May 14–20
- Songbird migration funnels through the river woods — warblers, orioles, and tanagers move north as western and eared grebes display on the potholes.
- The frost-free date arrives in the warm southeast — set out tomatoes, peppers, and warm-season transplants once nights stay above freezing.
- The wild prairie rose, the state flower, begins to bud toward its June peak as silky phlox and prairie violets dot the grass.
May 21–27
- Upland sandpipers whistle from fence posts over the grass, and bobolinks and dickcissels bubble over the wetter meadows.
- Monarch females lay on roadside and wetland milkweed to launch the first northern brood; butterflies puddle on damp pothole margins.
- Plains cottonwoods begin releasing their cottony seed, drifting it in white windrows along the Missouri and Red rivers.
May 28 – June 3
- The Prairie Pothole Region reaches full breeding tilt, with courting ducks, noisy Franklin's gull colonies, and yellow-headed blackbirds in the cattails.
- In the far north, set out tomatoes and squash only after the last frost passes in early June; direct-sow beans and short-season corn.
- Prairie smoke fades to its feathery pink seed plumes, and golden Alexanders and three-flowered avens color the mixedgrass prairie.
Birds This Month
May is one of the two finest birding months in North Dakota. The grassland specialties that draw birders from across the continent return to the native mixedgrass prairie: the skylarking song-flight of Sprague's pipit, the tinkling Baird's sparrow, chestnut-collared longspurs, Grasshopper and Le Conte's sparrows, and bobolinks and dickcissels in the wetter meadows. The Prairie Pothole Region is at full breeding tilt — courting ducks, displaying eared grebes and western grebes rushing across the water, and noisy colonies of Franklin's gulls, black terns, and yellow-headed blackbirds.
Shorebird migration peaks on the mudflats and pothole edges — marbled godwits, American avocets, Wilson's phalaropes, willets, and flocks of peeps. Songbird migration runs through the river woods and shelterbelts, with warblers, orioles, and tanagers funneling north. Western meadowlarks sing from every fence post, and upland sandpipers stand on posts giving their eerie whistle over the grass.
This month's tip: for the grassland specialties, walk into large blocks of native prairie at dawn — Sprague's pipit and Baird's sparrow sing in the calm early air and go quiet once the wind picks up.
What's Blooming
May is the prairie's first great flush of color. The prairie smoke opens across dry mixedgrass prairie, its nodding pink flowers giving way to the feathery smoke-pink seed plumes that name it. Golden Alexanders, blue-eyed grass, prairie violets, and the bright pink of three-flowered avens dot the grass, and the badlands flats brighten with scarlet globemallow and the first prickly-pear buds. In the wooded draws and Turtle Mountains, woodland ephemerals — large-flowered bellwort, wild ginger, and Canada anemone — bloom before the canopy closes.
The shrubs put on their show too: the white racemes of chokecherry and juneberry (saskatoon) scent the shelterbelts and river draws, and the buds of the wild prairie rose, the state flower, swell toward its June peak. It's the green-and-flowering heart of the short prairie spring.
Garden This Month
May is the big planting month across North Dakota, the short season finally swinging open. The frost-free date runs from about May 15 in the warm southeast to early June in the far north and Turtle Mountains, so watch your local frost odds before committing the tender crops. Once nights stay reliably above freezing, set out tomatoes, peppers, and the warm-season transplants you raised indoors, and direct-sow beans, sweet corn, cucumbers, squash, and pumpkins as the soil warms past 60°F.
Keep planting the cool-season succession — more lettuce, spinach, radishes, and carrots — and finish setting potatoes and onions early in the month. Harden everything off before transplanting, and keep frost cloth within reach; a late-May freeze still bites, especially in low spots and the northern counties. Mulch generously once the soil warms to conserve the moisture that a semi-arid prairie summer will demand, and stake young trees in the open against the wind.
Zone 3b (far north & Turtle Mountains): the last hard frost can come into early June here — set out tomatoes, peppers, and squash only at the very end of May and keep frost cloth ready. Cool-season crops and potatoes can go in earlier as the soil warms.
Zone 4a (central & west): the frost-free date falls mid-to-late May. Transplant tomatoes, peppers, and vine crops once nights stay above freezing, and direct-sow beans, corn, and squash after about May 20.
Zone 4b (southeast & Red River Valley): the earliest safe window — set out warm-season transplants by mid-month and direct-sow beans, sweet corn, cucumbers, and squash as the soil warms past 60°F.
What's at the Farmers Market
North Dakota's outdoor farmers markets open in May, and the early-season stands fill with cool-weather crops: asparagus, rhubarb, spinach, lettuce, arugula, radishes, green onions, and salad turnips, much of it from high tunnels and the first field plantings. The first strawberries from the warmest valley plots may appear at month's end. Greenhouse stands sell bedding plants and vegetable starts to gardeners racing the season.
The state's pantry staples are always present — hard red spring wheat flour, sunflower oil and seeds, dry beans, and honey — alongside eggs and the last storage potatoes and onions. Choose crisp, brightly colored greens and use them within a few days; trim and refrigerate rhubarb unwashed; and store asparagus standing in an inch of water in the fridge to hold its crispness.
Night Sky This Month
May nights are short and mild — a good time to enjoy North Dakota's dark skies in comfort before the briefest nights of summer. Theodore Roosevelt National Park in the badlands is the state's premier dark-sky site, and the empty grasslands of the Drift Prairie and Sheyenne National Grassland offer near-pristine darkness. Many regional astronomy clubs hold spring star parties under these skies.
The spring sky is at its best overhead: the Big Dipper rides high, its handle arcing down to brilliant orange Arcturus and on to blue-white Spica, while Leo swings into the west and the keystone of Hercules climbs the east, carrying the great globular cluster M13. Late in the night the summer Milky Way begins to rise in the southeast, hinting at the season ahead. North Dakota's far-north latitude keeps the aurora borealis a real possibility on active nights.
Exact planet positions change year to year — the printable North Dakota night-sky guide lists this season's planet visibility and the darkest accessible viewing sites near you.
Butterflies & Pollinators
May brings North Dakota's butterfly season into full swing as the prairie warms. The monarchs finally arrive — the females reaching the pothole country by late May and laying on the milkweed sprouting in road ditches and wetland margins to launch the first northern brood. Overwintered mourning cloaks and tortoiseshells still patrol the woods alongside the season's fresh emergences: cabbage whites, clouded and orange sulphurs, spring azures, the silvery silvery blue and Melissa blue, and the first painted ladies arriving from the south. Canadian tiger swallowtails drift through the wooded draws and Turtle Mountains. Tiny skippers begin appearing over the grass. The big grassland fritillaries — the regal and Aphrodite — are still in the caterpillar stage on prairie violets and won't take wing until late June and July. Watch for butterflies puddling on damp pothole margins, where they crowd together to pull salts and minerals from the mud.
What to plant for them is in the North Dakota native plants guide
Trees This Month
By May, North Dakota's trees are in full leaf and flower. The plains cottonwoods of the river gallery forest are fully leafed and, late in the month, begin releasing their famous cottony seed that drifts on the wind and piles in white windrows along the Missouri and Red. The shelterbelts bloom in sequence — the white racemes of chokecherry and juneberry, the lavender of planted lilacs, and the yellow of caragana hedges — while green ash and American elm leaf out and set their winged seeds.
The bur oaks in the Turtle Mountains and Pembina Gorge finish leafing out and hang their catkins, and the quaking aspens shimmer in full leaf. On the badlands slopes the Rocky Mountain junipers and ponderosa pines push fresh growth. The narrow wooded corridors that thread a prairie state are at their lushest now, a green relief against the surrounding sweep of grass.
The North Dakota native plants guide covers what grows with them
Weather & Daylight
Across North Dakota, a typical May day averages a high near 66°F and a low near 41°F, with about 2.7 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
Fresh and increasingly humid, 66F afternoons feel warm at last as heavier rains soak the greening landscape.
| Average high | 66°F |
|---|---|
| Average low | 41°F |
| Precipitation | 2.7 in |
| Sunrise (mid-month) | 6:02 CT |
| Sunset (mid-month) | 21:08 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 North Dakota's next month turns — what's arriving, blooming, and worth a night outside.
Go deeper with the North Dakota guides
The complete North Dakota birding, native-plant, and night-sky references — or the whole year, week by week, in one book.
Same month elsewhere: May in Ohio · May in Oklahoma · May in Oregon