Photographer: WXYZ
Copyright 2012 Scripps Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
Posted: 09/18/2012
(WXYZ) - Your senses tell you it's already fall! The changing leaves look at lot like autumn and our weather forecast sure looks like the season has already changed, but "officially" we're still in summer.
The truth is that most meteorologists toss the whole "astronomical" change of season into the garbage, and common sense tells us that it's not a very useful delineation, at least not in this part of the world.
Here's the deal. Two astronomical changes of season occur at the autumnal and vernal equinox, fall and spring respectively (approximately September 21 and March 21, but it can vary by a day or so either side) when the length of day and night are about equal. The start of astronomical winter and summer, respectively, occur at the solstices (approximately December 21 and June 21), when the sun is above the horizon for the shortest and longest amounts of time respectively.
The problem with these dividers of the seasons is that they seriously lag the warming and cooling of the seasons. To illustrate this, I'll ask you a question.
Let's say you have an outdoor project to do, one where you need to be out in the elements all day long. You've got a choice between two dates. You can do it on December 20th, or you can choose March 20th. Which date would you choose? (INSERT PAUSE AND TICKING CLOCK SOUND HERE)
Well, most of us who aren't trying to go skiing would prefer to do the outside work on March 20th, which is OFFICIALLY still winter, instead of December 20th, which is OFFICIALLY still fall. Good choice because here are the average high and low temperatures in metro Detroit on those dates:
December 20 is 35/23
March 20 is 48/30
But wait, you're saying you'd rather work outside in the winter than in the fall. Of course officially, that's what you're saying. The problem is with the late official arrival of the seasons. Instead, consider the way meteorologists define the seasons.
It's really simple, and it doesn't vary at all from year to year. To meteorologists, seasons are straightforward:
Fall: September, October, November
Winter: December, January, February
Spring: March, April, May
Summer: June July, August
So when you step outside tomorrow morning and this weekend and get chilled like you haven't been chilled in months, remember two things.
First, we told you it was going to get cold like this. And second, we're almost three weeks into fall already; it's supposed to get chilly during fall.
Follow Chris Edwards on Twitter at twitter.com/edwardswxwxyz
Copyright 2012 Scripps Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
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