Weather StoryAlmanac, microseasons, and the day's weather story.

Microseason 53 of 72 · September 21–25

Apples hang heavy on the branch

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.

  1. NENortheast Continental

    Apples hang heavy on the branch

    Upstate orchards open for pick-your-own — Honeycrisp leads.

  2. SESoutheast Subtropical

    Thunder quiets the land

    Summer thunderstorms cease abruptly; autumn quiet settles over the Lowcountry as heat relinquishes its grip.

  3. PNWPacific Northwest

    Fog locks the valleys

    Coastal marine layer and inland valley fog marry; the region enters weeks of persistent gray. Mist hangs through full days.

  4. CACalifornia Mediterranean

    Ceanothus blooms again

    California lilac (ceanothus) flowers in second spring bloom as autumn rains loom. Subtle shift palpable.

  5. MWMountain West

    Thunder retreats as the monsoon dies

    Late September brings the final monsoon surge south; by month's end, the daily storm pattern collapses.

  6. MPPlains Continental

    Thunder stills across the plains

    Afternoon thunderstorm season wanes. Winds shift to more northerly flow. The landscape cools and dries. Monarch migration continues in waves through the region.

  7. SWSouthwest Desert

    Thunder finally silent

    Monsoon rains cease; the desert dries rapidly under cloudless skies.

  8. TRTropical / Sub-Tropical

    Storm intensity ebbs slightly

    Late September sees hurricane activity moderate fractionally; the most violent organizing phase shifts northward.

  9. AKAlaska Subarctic

    Moose in rut, bears in den

    Moose calling reaches crescendo; grizzly and black bears retreat to dens as food scarcity intensifies.

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.