Summer is almost history if you reckon seasons meteorologically instead of by the calendar. According to meteorologists, autumn begins on September 1. That’s because they define the seasons according to climate characteristics. Long ago they decided that June 1 more closely resembles the temperatures of summer then those of spring. And they deem typical weather the first week of September to be more fall-like than summerlike.
Let’s play along, for now. After all, teachers and students are almost back in school and the beaches are emptying. But since this page is devoted to the sky, we’ll focus there to see whether the heavens currently resemble autumn more than summer.
Consider six overhead items. Number One: cumulus clouds. These cauliflower-shaped lowish clouds are everyday features in summer, but very rarely seen during our winter months. So what about now, in September? The answer: They’re still around. That’s because they are caused by rising air currents, which are created by strong sunlight warming the ground. That’s why a summer morning that is cloudless at 8 or 9 a.m. typically morphs into a late-morning sky dotted with cumulus clouds. Bottom line: The present sun is still strong enough to create them. But enjoy them while they last; by November they’ll be rare.
Item Number Two: rainbows. Around here, we have a distinct rainbow season: summer. We almost never get rainbows in the winter. That’s because a rainbow requires simultaneous sunshine as well as a rainshower. So you need those scattered cumulus rain clouds, with breaks in between that allow sunshine through. In Hawaii that’s a daily situation, which is why rainbows are so common there. But here in the Hudson Valley, we are now nearing the end of our rainbow season.
Item 3: overcast. Completely cloudy skies are sadly the norm during our cold half of the year, from November through April. Such gloom is much rarer in summer.
More info: If you live around here, the sky is cloudy two-thirds of the time from November through April. But everything reverses come May and especially June, when the sky stays blue two-thirds of the time through October. So we definitely have a sunny season and a cloudy season. Right now we are still enjoying the clear section of the year.
Item 4: the starry heavens. The year’s best stargazing conditions happen right now and last through October. This is when the air is driest and the stars are most vivid. Plus, the Milky Way is at its best of the year. This is a case where you’d vote neither for summer nor for winter, but for autumn itself.
Item five: the Moon. Annually, there are only two Full Moons with official names. These are the Harvest Moon, which appears this year on September 14, and the Hunters’ Moon on October 13. Visually, neither of them stands out. Neither is particularly high up or low down, or particularly close or far, or reddish or white. Observationally, they are simply normal-looking Full Moons.
Item Six: the canopy. Looking up doesn’t automatically mean the sky. Thanks to the minority of invariably maverick-turning maples and sumacs, we’re soon going to get blasts of crimson that draw visitors from around the world. This overhead chromatic brilliance doesn’t, of course, belong to any other season.
Overall, it would seem you could call this summer or fall – your pick.