I saw the first signs of fall the other day - two yellowing cottonwood leaves liberally tinged with leftover green splotches from summer. These were on the ground, not on the tree, and in fact I could see no yellow in the tree itself. Truth be told, an occasional yellow leaf anytime during the growing season is not that unusual, the product of some localized injury to the tree perhaps, or perhaps the result of drought or infestation. But leaves that change in response to some seasonal imperative look different. They have an undefined and perhaps indefinable quality that says their changes are in response to subtle changes in the environment.
I can’t explain this and I cannot give specific evidence of what makes the yellowed cottonwood leaf of fall different from one yellowed from disease or drought. It is a feeling and as such is inherently irrational. This is not to say that such feelings not based on strict science are wrong, but for now at least they cannot be proved.
In any event I believe that these leaves were the sign of the first faint whispers of fall. Today there were considerably more such leaves on the ground under the cottonwood, some fully yellow. This is evidence, I believe, that my initial assessment was correct. It is still warm here, even hot during the day, but nighttime temperatures have begun a slow decline, and some recent late nights have demanded long sleeves or even a sweater. This is not unheard of even in mid-summer, but there seems to be a trend.
Astronomically, fall begins when the earth passes a specific point in its orbit where the planet is not tilted toward or away from the sun. This is called an equinox, meaning “equal night.” Theoretically, there should be 12 hours of daylight and 12 hours of dark on that day, but the effects of the atmosphere change that slightly. In the northern hemisphere the beginning of fall is called the “autumnal equinox” and it marks the astronomical beginning of the season. (However, in the southern hemisphere spring begins at the same time.) This year it is at precisely 5:51 a.m. EDT on Sunday, September 23.
However, climatological fall can come earlier or later than astronomical fall. It may be signalled by a change in the weather, yellowed leaves, bird or animal migrations, or there may be even more subtle clues. What about in your area? What do you look for to signal the onset of autumn? When does fall fall, and how do you detect it?
Larry Sessions
Denver
Fall is when the Longhorns kick off the football season with their first victory!
Shaun
Austin, TX
I used to think fall began right after the first cool night of summer, but I’m sad to say fall now begins the first time I see the sun’s already setting when I leave the office.
Those are really interesting ways of looking at it. Fall comes when YOU believe it is here, not just by the calendar or the motion of the Earth. The latter gives a good and specific point to hang our concerns on, but the feeling is when fall really begins. And for anyone who is a true Texacan — or has just lived in Texas for any time — knows that it truly is fall when football starts up again, although I would argue that it would be with a win or without!
LS
I forgot to mention, but the two leaves in the photo are from 22 August. Last evening (27 August), after I had written the blog, I noticed not only more yellow leaves on the ground, but small clumps of yellow at the tops of the two cottonwood trees nearby. To me this is definitely evidnce that the yellow leaves are more seasonal than due to disease, infestation or drought — to me it is definitely evidence that the seasons are changing.
Not to mention the fact that our nearby “Big Lots” is all decked out for Halloween and already has several aisles of Christmas toys and decorations!
LS
Fall seems to have arrived in the Rhineland. The plum trees are dropping their yellow leaves about.
Hi Larry,
I wonder if we can still stick to the 23 rd September ’stsrt’ to Fall or Spring.
When I came to Guyana, a number of years ago, the talk was of the May / June rains. Now with all the climate changes the rains still continue well into late August, and the temperatures vary accordingly.
Perhaps Fall/Spring start should join the list of ‘moveable’ dates?
George
This morning when I walked outside it “FELT” like fall ….the air is different ..maybe cleaner… it felt great.Im usually a spring fan but this year is different!I think the air even smells different!
Mark, George and Diane.
I think that aside from any consideration of global warming and climate change, there would be years in which the conditions for a change in seasons happens significantly before or after the astronomical markers of solstice and equinox. And in fact, from what I have read the signal of a change in climate has been, from the geologic record, a period of unsettled weather where things don’t quite seem to be where they should be, such as summer weather in fall, spring like weather in winter and so on. But I think for the time being we have to maintain those astronoical definitions unless we are willing to declare fall in the Rhineland at the same time it is mid-summer (by the thermometer) in Arizona. Like Time Zones, the astronomical seasonal definitions help keep us on the same page if not all at the same traditional “season.”
I certainly agree with Diane that there is a big component of “feeling” in our thoughts about the seasons. It has felt like fall for me for a while now, well before the astronomical definition applies. For me it feels dry, and can be warm but with a breeze, and nature is quieter than in Summer. Maybe there are crickets in the middle of the daytime, even amid the chorus of cicadas. I have always been a fan of fall, probably because as a kid it summoned the best time of year, from Halloween through Christmas!
LS
Hi Larry,
I think Diane hit the nail on the head.
It is the ‘feel’ of the time of year rather than the date.
As children, it was a challenge to find the first primrose or birds nest but there was a ‘feel’ in the air inspite of changeable weather at a particular time.
Larry, your comments of the best time of the year as a kid, Halloween to Christmas, brings back very happy memories. By the way, a greater change has come about for children now. We used to send our letters to Santa Clause by putting them up the chimney. With all the modern heating systems that is often no longer possible.
We still have an open fire, perhaps adding to the global warming, and Santa still comes.
George
Hi Larry, we swim in a large natural springs pool near our home, and it’s there that we notice the shift from summer to fall.
Every August, in the early morning at the pool, the water becomes choppy. Not sure why. Maybe winds during the night? Or a cooler temperature at night? At any rate, the choppiness of the water at our beloved pool on August mornings is always a sure sign of autumn on its way.
Deborah
George,
By the end of summer I typically was ready for school to start again, and although I actually always thought of Halloween as kind of a silly observance, I looked forward to it because it meant that fall was in full swing and that the holiday season really had begun. I really have always loved fall, but in part it may be because I looked so much forward to Christmas. As a nerdy kid whose mother worked at Woolworth’s I always bought all my Christmas presents (my Mom gave me the money) at the employee open house, usually in late August as I recall. It was fun and the high point of my life. So I loved fall and winter up until Christmas. Then on Christmas day it all fell apart because I knew it was over for another year! I remember stockings with nothing but apples, oranges, nuts and may be candy, but I don’t remember putting Santa’s letters up the chimney (in large part because we had no fireplace!).
Debbie,
I should report that as of today (10 September) there are many more signs of fall, although no mass change of leaves, just the random cluster here and there. But today it is chilly (50s) and rainy here in Denver. It may get a bit warmer, but Summer is definitely gone.
LS
Larry,
I wouldn’t discount summer just yet! The weather across the entire Earth is becoming more and more erratic … one might say “unseasonable.” Denver could have a long Indian summer yet to come …
Then again, with the whole climate changing, all bets are off. So who knows?
In the years ahead, our old-fashioned thoughts of “my town has this or that particular climate” might need serious adjustment. Maybe thoughts of a particular climate in a particular place won’t apply anymore … at least not as it did in the period of climate stability that you and I have lived through most of our lives.
D