Microseason 27 of 72 · May 11–15
Shad run up the rivers
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
Shad run up the rivers
American shad migrate up the Hudson to spawn.
- SESoutheast Subtropical
Shad pulse upstream through rapids
American shad and hickory shad spawn up Atlantic-draining rivers. The Roanoke and Savannah surge with silvered bodies.
- PNWPacific Northwest
Earthworms Rise to Feed the Forest
Earthworms emerge after spring rains, turning soil and enriching humus. Salmon fry hatch in gravel redds; smolts continue leaving for the ocean. Fiddleheads finish unfurling.
- CACalifornia Mediterranean
Redwood coast in cool shade
Coast redwood understory lush with sorrel and ferns, fed by fog drip. Interior heat climbs; coastal routes become crucial wildlife corridors.
- MWMountain West
Snowmelt crests toward the divide
Streams peak with snowmelt thundering down granite canyons. Mountain goats descend from highest snowfields to moist meadows.
- MPPlains Continental
Seedlings Rise From Frost-Free Soil
Final frost danger passes; corn tassels begin emerging; warm-season growth accelerates dramatically across the region.
- SWSouthwest Desert
Heat reaches extremes daily
Highs hit 110°F; all wildlife nocturnal; ground surface cracks.
- TRTropical / Sub-Tropical
Green life breaks upward
New growth erupts everywhere—mangrove roots, understory seedlings, fern fronds. Wet season at its most fecund.
- AKAlaska Subarctic
Rivers run milk-white with glacial melt
Glacial runoff peaks; Susitna, Kenai, Copper rivers all surge with snowmelt. Salmon ascend into stronger current. Brown bears hunt side channels.
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.