"The First Day of Winter, and; Why the Shortest Day of the Year Doesn't Feel Like the Shortest"

Scheduled air date: 2001 Dec 17-23


Winter Solstice—the beginning of Winter—occurs December 21st for the Northern Hemisphere.  At this time, the Sun's path across the sky is at its lowest, or closest to the southern horizon, while the Moon's path is at its highest.


For comparison, the above shows the paths of the Sun and Moon across the sky at Summer Solstice—the beginning of Summer (June 21st).  Note that, relative to Winter Solstice, the Sun and Moon appear to have switched places.
(Positions shown at one- hour intervals for mid-Northern latitudes.  The Moon's symbol in the above illustrations is intended to show the Moon's path and not its phase, which is near First Quarter on the Winter Solstice this year.)


At the Vernal (Spring) Equinox, the Sun rises due East and sets due West.  It then rises slightly farther North with each day, until it reaches its Northernmost position at the Summer Solstice, the longest day of the year.  After Summer Solstice, the Sun reverses its direction, rising slightly farther South with each day, passing through Autumnal (Autumn) Equinox and then reaching its Southernmost position at the Winter Solstice, the shortest day of the year.
Winter Solstice occurs on December 21st this year, but as the earliest sunsets occur about 2-3 weeks before the Winter Solstice, those days usually seem shorter to us.  The latest sunrises occur 2-3 weeks after Winter Solstice.
(Illustration and explanation are for Northern-hemisphere observers.)

If you wish to view illustrations for other episodes, please see our Star Gazer Illustrated directory.


Illustrations on this page were created using TheSky Astronomy Software, an advanced desktop planetarium program designed for Windows.

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