Microseason 54 of 72 · September 26–30
Geese begin to chevron south
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
Geese begin to chevron south
Canada goose V-formations cross the sky on northwest winds.
- SESoutheast Subtropical
Insects retreat below
Crickets grow sluggish; insects tunnel deeper into soil and leaf litter as autumn cool drives life underground.
- PNWPacific Northwest
Geese stage southward
Tundra swans and Canada geese mass in the Skagit and other river valleys, eating and resting before crossing mountains and deserts.
- CACalifornia Mediterranean
Insects retreat below
Insects burrow deep as temperatures swing wider. Chaparral smells sharper—sage and bay laurel volatile.
- MWMountain West
First frost hardens the high valleys
Deep freeze arrives across the basin; killing frost ending the last alpine wildflowers and signaling true autumn's grip.
- MPPlains Continental
Snow geese wheel through the flyway
Sandhill crane flocks appear on migration through the Platte Valley. Snow geese and Canada geese begin to chevron south through the Central Flyway. The prairie fills with the sound of geese.
- SWSouthwest Desert
Insects burrow deep
Desert insects and arachnids dig into soil and leaf litter before winter.
- TRTropical / Sub-Tropical
Late-season storms persist
The final week of September remains active; storms continue tracking through the Atlantic and Caribbean basins.
- AKAlaska Subarctic
First heavy snow on the high country
Snow depth increases dramatically above two thousand feet; interior valleys see accumulation begin in earnest.
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.