Microseason 47 of 72 · August 21–25
First cool morning surprises
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
First cool morning surprises
A Canadian high delivers the season's first taste of fall air.
- SESoutheast Subtropical
Heat breaks in creek beds
First cool mornings creep in after dense fog blankets swamp and bottomland, cicadas briefly silenced by the chill.
- PNWPacific Northwest
First sweater morning
The dew point drops. A morning arrives where breath clouds visibly and fleece feels necessary by dawn. Summer heat's grip loosens.
- CACalifornia Mediterranean
Marine layer descent
Cool fog rolls inland from Pacific early morning. First hint of autumn chill on the coast.
- MWMountain West
The monsoon breaks into scattered showers
Afternoon storms fade; mornings cool sharply, frost threatening high gardens for the first time since spring.
- MPPlains Continental
Dew settles on the tallgrass
Mornings drop below 60°F, frost is still weeks away but coolness returns to dawn air. Monarch numbers swell as northern populations begin drift south.
- SWSouthwest Desert
Monsoon's final breath
Afternoon haboobs and lightning strike; monsoon rains dwindle toward summer's end.
- TRTropical / Sub-Tropical
Trade winds gather strength
Trade winds intensify off the Atlantic, bringing cooler air and the first whispers of hurricane season's approach.
- AKAlaska Subarctic
Termination dust crowns the peaks
First snow dusts high summits; the fireweed clock ticks toward transition as summer yields its grip.
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.