April is full spring on the Snake River Plain — arrowleaf balsamroot golds the foothills, sage-grouse leks reach their peak, and the first long-distance migrants pour back into Idaho. The mountains are still deep in snow, so the season runs hardest in the low valleys and canyon grasslands.
Week by week in April
April 2–8
- Greater Sage-Grouse leks reach their dawn peak on the sagebrush flats, and American White Pelicans and grebes return to the reservoirs.
- Arrowleaf balsamroot golds the Boise Front and canyon slopes, threaded with the first blue lupine and scarlet paintbrush.
- Milder nights open the central-Idaho dark-sky country; the Big Dipper's handle arcs to Arcturus and on to Spica climbing the east.
- Set out broccoli, cabbage, and kale transplants and plant strawberries and bare-root canes across the lower valleys.
April 9–15
- Bullock's Orioles and Black-headed Grosbeaks arrive in the cottonwoods, and Calliope and Rufous Hummingbirds reach the foothill feeders.
- Bitterroot buds and rose-pink Lewisia open on the lithosol scablands while yellow bells and desert parsley fill the warming ground.
- Serviceberry, chokecherry, and golden currant flower along the riparian edges as the river cottonwoods and aspens leaf out.
- The first field asparagus arrives from the warm river valleys alongside tender spinach, radishes, and salad turnips.
April 16–22
- Western and Clark's Grebes begin their rushing courtship runs on the reservoirs, and White-faced Ibis return to the wetlands in glossy flocks.
- The Lyrid meteor shower peaks around April 22, radiating from near Vega in the dark northeastern sky over the high desert.
- Western Spring Azures, Spring Whites, and the first Western Tiger Swallowtails join the Sara Orangetips on the warm foothill slopes.
- Direct-sow more carrots, beets, and chard and harden off tomatoes and peppers for the coming May planting date.
April 23–29
- Lazuli Buntings and Western Tanagers return to the foothill brush, and shorebirds stop on the drying mudflats during spring passage.
- The Camas Prairie greens toward its famous bloom as wild blue flax, scarlet gilia, and mariposa lilies open on the foothill slopes.
- Asparagus, rhubarb, and the first cutting greens fill the opening outdoor farmers markets across the state.
- Western larch pushes its first soft, bright-green needle tufts among the dark conifers of the north-Idaho panhandle.
Birds This Month
April is a flood of returning birds in Idaho's lowlands. Greater Sage-Grouse leks reach their dawn peak on the high-desert flats, and the Snake River Birds of Prey NCA is at its raptor height — Prairie Falcons and Golden Eagles on eggs in the canyon, Ferruginous and Swainson's Hawks back on territory, and Burrowing Owls standing at their ground-squirrel burrows. American White Pelicans, Western and Clark's Grebes, White-faced Ibis, and Black-necked Stilts return to the wetlands and reservoirs.
Songbird migration builds: Yellow-rumped Warblers, Orange-crowned Warblers, Vesper and Lark Sparrows, Western Meadowlarks in full song over the sagebrush, and the first Bullock's Orioles and Black-headed Grosbeaks late in the month. Sandhill Cranes are paired on the eastern Idaho meadows, Long-billed Curlews display over the Camas Prairie, and Calliope and Rufous Hummingbirds arrive at the foothill feeders.
What's Blooming
April is the foothills' golden month. Arrowleaf balsamroot covers the Boise Front and the canyon and sagebrush slopes statewide in sheets of sunflower-yellow, threaded with the deepening blue of silvery and silky lupine and the scarlet of early paintbrush. The lithosol scablands open bitterroot buds and the rose-pink of Lewisia, while yellow bells, spring beauty, larkspur, and desert parsley (Lomatium) fill the warming ground.
The Snake River canyon grasslands and the lower Salmon and Clearwater breaks — Idaho's mildest, earliest country — are at their finest now, the steep hillsides painted yellow and blue. The Camas Prairie is greening but still weeks from its famous bloom, and the high Sawtooth and Lost River meadows are buried in spring snow. Along the rivers, the serviceberry and chokecherry flower white, and golden currant scents the riparian edges.
Garden This Month
April is the heart of the cool-season garden in Idaho's lower valleys. In the Treasure Valley and southwestern fruit country, direct-sow carrots, beets, lettuce, spinach, peas, chard, and radishes, plant seed potatoes and onion sets, and set out cold-hardy broccoli, cabbage, kale, and cauliflower transplants. Plant strawberries, bare-root cane berries, and asparagus crowns, and harden off the tomato and pepper starts on the porch for their May planting date.
Idaho's clear-sky springs bring hard, late radiational frosts, so keep row cover and walls-of-water ready and resist setting out tender crops too soon — the safe date runs from late April in the warmest valleys to June in the mountains. In the eastern Snake River Plain and high valleys, the season is just cracking open; sow only the hardiest greens and peas as the soil dries. Mulch and consistent water set up the famous summer crops — sweet corn, potatoes, and onions — that the long, hot Idaho days will drive.
Zone 4b (eastern Snake River Plain & mountain valleys): the season cracks open late. As beds thaw and dry, sow the hardiest peas, spinach, and radishes under row cover, but hold everything tender — frost-free nights are still weeks away.
Zone 5b (Boise foothills & Magic Valley): direct-sow peas, spinach, radishes, lettuce, carrots, and potatoes, and set out hardy brassica transplants. Keep tomatoes and peppers indoors a while longer — the last frost still runs into May here.
Zone 6a (warmest Treasure Valley & lower Snake River): the cool-season garden is in full swing. Direct-sow carrots, beets, lettuce, peas, and chard, plant potatoes and onions, set out brassica transplants, and harden off tomatoes for a May planting. Plant strawberries and bare-root canes.
What's at the Farmers Market
April markets in Idaho show the first true taste of spring. Greenhouse and high-tunnel growers around Boise, Twin Falls, and Moscow bring tender spinach, lettuce, arugula, green onions, radishes, and the first cutting greens, and the year's earliest field crops — rhubarb and overwintered green garlic and chives — appear at the warmest valley stands. Stored Idaho potatoes and Treasure Valley onions still anchor the table, holding firm from the cellars.
The Palouse and southern Idaho keep supplying dried lentils, split peas, and chickpeas, and value-added Idaho goods fill out the stand — honey, fresh-milled flour and grain, hard cider, and wine from the Snake River Valley appellation. As more spring markets open across the state, choose crisp, bright-colored greens and refrigerate them promptly, snap rhubarb that is firm and glossy and store it cold, and keep the last storage potatoes cool, dark, and dry.
Night Sky This Month
April is one of Idaho's best stargazing months — milder nights, snow clearing from the lower dark-sky sites, and still-long darkness before the short summer twilight. The Central Idaho Dark Sky Reserve around the Sawtooths, Stanley, and Sun Valley reopens for comfortable viewing as the high passes melt out, and Bruneau Dunes State Park runs full spring observatory sessions south of the Snake. The high desert and the Lost River country offer wide, transparent skies away from the valley lights.
The spring sky is at its finest: Leo rides high, the Big Dipper stands overhead with its handle arcing to brilliant Arcturus in Boötes and on to Spica in Virgo, and the faint galaxies of the Virgo Cluster lie within reach of a telescope under truly dark skies. The Lyrid meteor shower peaks around April 22, radiating from near Vega in the northeast. For this year's exact meteor timing and planet positions, see the printable Idaho night-sky guide.
Butterflies & Pollinators
April brings Idaho's butterfly season to life in the low country. The warm foothill grasslands and canyon slopes of the Treasure Valley, Boise Front, and the lower Snake, Salmon, and Clearwater rivers come alive with the bright wingtips of the Sara Orangetip, the season's first Western Spring Azures, Spring Whites, and the small coppers and blues nectaring on the early balsamroot and lomatium. The Anise Swallowtail patrols bare hilltops and lava ridges.
Overwintered adults — Mourning Cloak, Milbert's and California Tortoiseshells, and the anglewings — are still on the wing alongside the new generation, and the first Western Tiger Swallowtails may appear in the river bottoms by late month. The high mountains, the Camas Prairie, and the Sawtooth meadows are still under snow, their butterfly flight months away, so April's activity is concentrated on the sun-warmed lowland slopes where spring runs earliest.
Trees This Month
April leafs out Idaho's valleys. The riverside black cottonwood, quaking aspen, water birch, and willows break into fresh green along the Snake, Boise, and Clearwater corridors, and the native serviceberry, chokecherry, and Rocky Mountain maple flower white along the canyon edges and foothill draws. Golden currant and wild plum scent the riparian thickets, and in town the ornamental cherries, plums, and maples fill the streets with bloom.
In the forests the conifers begin their spring work: Douglas-fir and ponderosa pine swell their reddish pollen cones on the lower mountain slopes, and the deciduous western larch of the north-Idaho panhandle pushes its first soft, bright-green needle tufts among the dark western white pine, redcedar, and hemlock. Higher up, the Sawtooth and Lost River forests are still snow-bound and dormant, their spring flush weeks behind the warming valleys below.
Weather & Daylight
Across Idaho, a typical April day averages a high near 53°F and a low near 30°F, with about 2.2 inches of precipitation — statewide averages from the 1991–2020 U.S. climate normals.
A real thaw arrives, low-50s afternoons feel almost mild, though cool nights near freezing and frequent showers keep jackets zipped.
| Average high | 53°F |
|---|---|
| Average low | 30°F |
| Precipitation | 2.2 in |
| Sunrise (mid-month) | 6:56 MT |
| Sunset (mid-month) | 20:22 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 Idaho's next month turns — what's arriving, blooming, and worth a night outside.
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Same month elsewhere: April in Illinois · April in Indiana · April in Iowa