Sunday at 6:03 PM (EST) was the Winter Solstice. This is an astronomical event that occurs because our world is tilted on its axis with respect to our orbit around the sun, a fact that explains the seasons in our temperate zones.
Late dawn. Early sunset. Short day. Long night. The shortest day and the longest night of the year. It marks a turn in the seasons as the length of the days get longer.
|Courtesy of NOAA|
If the days begin to get longer, why do the coldest days of the winter season fall after the Winter Solstice? According to the National Climatic Data Center the coldest days fall between December 1 and March 31 with 83% of those from December 20 to March 31.
The Washington Post’s Weather Gang reports that “even though daylight slowly increases after the solstice, many places don’t see their coldest days until mid-January. This happens because the Northern Hemisphere continues to lose more heat than it gains for several more weeks. The oceans – which take longer than land to heat up and cool down – play a role in this seasonal temperature lag. Only after the Northern Hemisphere starts to receive more solar energy than it loses do average temperatures begin their upward ascent.”
Doug Wenztel of the Shaver’s Creek Environmental Center says there’s a bright side as well. This is an opportunity to go out and explore your local areas and see a different landscape.
A walk along a favorite summertime wooded path reveals the shapes of trees and their branching patterns. Sit still and quiet for 15 minutes and soon you will see the birds that stay with us all winter. Discover mosses and evergreen ground covers nestled against the rocks near the path or check the edges of a pond for ice crystals.
You most likely will hear the rustle and rattle of dead leaves still clinging to the branches of some trees. In an earlier Penn State post, “Winter Leaves that Hang On,” Jim Finley asks if you have ever wondered why some trees hold their leaves into the winter months.
“Marcescence, the term used to describe leaf retention, is most common with many of the oak species, American beech, witch hazel, hornbeam (musclewood), and hophornbeam (ironwood).
Normally, as deciduous trees (which include hardwoods and some conifers) prepare to shed their leafy summer coats, cells at the interface between the twig and the end of the leaf stem release enzymes and form an abscission layer that “unglues” the leaf – separating it from the vascular bundles, allowing it to fall free.
All trees shed leaves, even conifers; however, they generally retain their needles for more than one year. Leaf drop benefits deciduous trees by reducing water loss and allows them to develop leaves that efficiently use available sunlight during warmer seasons.”
Read Finley’s full article for more information on why trees may retain their leave through the winter months and he makes a good point when he says, “… think about the bit of shelter they provide for wintering birds as they perch among the rattling leaves, away from winter’s wind.”
For other information about the Winter Solstice
State College.com: Winter Solstice Marks Beginning of Stormy Season