WYSO

Poor Will's Almanack: September 12 - 18, 2017

Sep 12, 2017

Fall doesn't come all at once with equinox; it's been coming since the 26th of June when the days started to grow longer again, the Northern Hemisphere tilting away from its source of heat.

The sun rose from the east northeast and set west northwest three months ago; now it rises almost due east, sets due west. Dawn and dusk continue to move south at the rate of about one degree every 72 hours until December solstice.

The night sky is changing too, the stars predicting winter. By nine o'clock, Cygnus the swan migrates overhead through the Milky Way, facing southwest into Sagittarius.  Winged Pegasus, is poised in the east. By ten o'clock, the infallible sisters of Autumn, the Pleiades, will have risen behind Bellerophon's steed; and then Taurus will come up, and Aldebaran, precursor of January. Orion follows after midnight. The way ahead is clear enough.

Average temperatures, which varied only one or two degrees at the height of Middle Summer, dropped a full four degrees in August, and now fall four degrees almost every week. Lows will soon go below 50, highs below 70 degrees, until May.

Nearly 200 species of birds have begun to leave the state by equinox. Only about 60 remain, and those will be on their way at the close of October. By that time, the signs will be unmistakable. Insects will be disappearing. Leaf color will have peaked, and all of the wildflowers except a few asters, goldenrod, Queen Anne's lace and chicory will have gone to seed.

This is Bill Felker with Poor Will’s Almanack. I'll be back again next week with notes for the second week of early fall. In the meantime, go outside after midnight and find the Pleiaes, a tight cluster of stars rising over the eastern horizon.