Microseason 15 of 72 · March 11–15
Peepers call from the marsh
A five-day window of the year, read through nine North American climate regions.
Same week, nine climates
A microseason names a five-day window of the solar year. What that window actually looks like on the ground depends on where you are. Below, the same calendar window read through each of nine North American climate regions.
- NENortheast Continental
Peepers call from the marsh
Spring peepers — tiny frogs — fill wetlands with loud chorus.
- SESoutheast Subtropical
Dogwood and redbud ignite
Eastern redbud cascades pink and magenta; flowering dogwood whites and pinks burst across every hillside.
- PNWPacific Northwest
The Spring Salmon Peak
Spring Chinook runs crest. Thousands of silver-bright kings occupy every substantial river from the Columbia to the Fraser. The cycle turns fully now.
- CACalifornia Mediterranean
Blossoms crown the hillsides
Peak wildflower bloom: poppies, lupines, sage, ceanothus in simultaneous flower. Morning temperatures warm to 70°F. Hummingbird territories fully established. Golden eagles nest-building.
- MWMountain West
First blooms open to the spring sun
Pasqueflowers bloom purple on south slopes; avalanche and glacier lilies burst from snowmelt zones; beargrass and blanket flower leaf out.
- MPPlains Continental
Spring arrives with fury and grace
Mid-March brings volatile weather—warm days and sudden freezes—as spring claims the plains.
- SWSouthwest Desert
Saguaro flowers crown the desert
Saguaro blossoms opening—creamy white flowers with purple stamens. Late wildflowers fading. Daytime heat 97-100°F. Nights warming to 45°F.
- TRTropical / Sub-Tropical
Fruiting cycles deepen as rains persist
Mid-March—wet season solidifies. Fruiting everywhere: mahogany, ceiba, royal palm, ausubo dropping seed. Trade winds weaken. Warmer water supports explosive plankton blooms.
- AKAlaska Subarctic
Breakup clock begins its countdown
The Nenana Ice Classic approaches; Tanana River ice groans as meltwater accelerates, signaling imminent breakup.
About the 72-microseason calendar
A microseason is a five-day window of the solar year — long enough to notice something change, short enough that the change is specific. The year holds seventy-two of them, six per month, ordered by what the natural world is doing rather than what the clock says. Almanac calendars like this are an old American habit, kept by farmers, gardeners, and birders for centuries; Weather Story collects them into a single reference.
Each microseason is read through nine North American climate regions. The phenological events that mark a five-day window vary with ecology — the strawberries that open in the Northeast might coincide with the first magnolias dropping in the Southeast and the salmonberry blossoms unfurling in the Pacific Northwest. Same week, nine ecologies, nine readings.