Microseason 57 of 72 · October 11–15
Frost paints the garden black
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
Frost paints the garden black
First hard frost kills tender annuals overnight.
- SESoutheast Subtropical
Asters crown the meadows
Late-blooming asters reach full purple glory across the Coastal Plain; chrysanthemums unfold in gardens as native flowers fade.
- PNWPacific Northwest
Frost's first mark
Overnight temperatures dip below freezing on clear nights. Tender plants blacken. The growing season ends. Frost patterns jewel windows.
- CACalifornia Mediterranean
Wildflower anticipation
Chaparral still parched. First major atmospheric river visible on models 7–10 days out. Waiting.
- MWMountain West
Snow settles on the high passes
Significant snowfall above 10,000 feet; winter arriving a full month before the calendar, the peaks already white.
- MPPlains Continental
First widespread freeze arrives
Hard frost kills remaining herbaceous plants. Tallgrass prairie frosted and darkening. Gardens blackened. Still warm afternoons, but nights now regularly below freezing.
- SWSouthwest Desert
Brittle beauty blooms
Second spring: brittlebush and desert lupine flower; brief warmth triggers blooms.
- TRTropical / Sub-Tropical
Seasonal wind shift emerges
Late October brings the first sustained tradewind patterns from the northeast; hurricane season's grip loosens perceptibly.
- AKAlaska Subarctic
Twilight deepens to darkness
Fairbanks slips below five hours of daylight; the transition toward polar night accelerates dramatically.
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.