The seasons in Philadelphia
Autumn. 11 h 10 min of daylight.
Autumn in Philadelphia by the sun, until the solstice on 21 December at 3:50 PM EST; by the meteorological calendar too, since 1 September.
Spring
20 Mar
The equinox at 10:45 AM EDT. By the calendar, 1 March.
Summer
21 Jun
The solstice at 4:24 AM EDT. By the calendar, 1 June.
Autumn
22 Sep
The equinox at 8:05 PM EDT. By the calendar, 1 September.
Winter
21 Dec
The solstice at 3:50 PM EST. By the calendar, 1 December.
The sun through the year.
You stand at the middle of your horizon. The dots are the sun’s path that day, the sun at its highest. Walk the year and the path grows and shrinks with the seasons, or drag the sky to turn it.
Autumn by the sun and by the meteorological calendar.
How it knows.
The turning points, to the minute
The equinoxes and solstices are the instants the sun’s apparent longitude reaches 0°, 90°, 180° and 270°, worked out by Meeus’s method and read in this place’s clock, its clock changes included. The method is good to about a minute across this century.
Two conventions, both named
The calendar seasons are not Sol’s to define, so the page cites the body that describes them, and names the local one first: the Bureau of Meteorology, the Met Office and the National Weather Service. The hemisphere decides the names, and neither convention is a forecast of the weather.
Day length
Sunrise to sunset, the sun’s upper edge on the horizon, for every day of the year at this place, by the engine the daylight pages use. The longest and shortest days are read from that table, which is why they can fall a day from the solstice. Each city’s year is published beside its page as JSON, CC BY 4.0.
The next turning point, elsewhere.
Los Angeleswinter · 21 Dec 12:50 PM San Franciscowinter · 21 Dec 12:50 PM Seattlewinter · 21 Dec 12:50 PM Denverwinter · 21 Dec 1:50 PM New Yorkwinter · 21 Dec 3:50 PM Londonwinter · 21 Dec 8:50 PM Melbournesummer · 22 Dec 7:50 AM Where you standany place, in your browserA year of light.
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