Metro

Dave Epstein

Brace yourselves: It’s about to get darker. And darker. And darker.

Before those 4:11 p.m. sunsets arrive, we have a lot of transformations. Some are clear, while others are more subtle and require a keen eye to see.

Suzanne Kreiter/Globe Staff

Before those 4:11 p.m. sunsets arrive, we have a lot of transformations. Some are clear, while others are more subtle and require a keen eye to see.

It happens every year, yet it is still somewhat of a shock to our collective psyche. I’m talking about the rapid loss of daylight we are all experiencing right now and all the other things that go along with it.

Here’s the thing: While the lack of light will continue to become worse, nature is responding in amazing ways, truly wonderful to observe. Before those 4:11 p.m. sunsets arrive, we have a lot of transformations. Some are clear, while others are more subtle and require a keen eye to see.

A swift metamorphosis begins

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This week kicks off the three-month period when temperatures fall most rapidly and the one-month period when day length decreases the fastest. Over the next three weeks, we will actually lose about an hour of daylight. Last weekend, we enjoyed about 13 hours of daylight each day, but by the end of the month, the gap between sunrise and sunset falls to under 12 hours. All of this signals huge changes to nature. Areas that were bathed in warm summer sunlight eight weeks ago now remain cool, within increasingly expanding midday shadow.

Light loss is not uniform

You might assume the loss of light is uniform from the time it begins after the summer solstice to the time it ends on the winter solstice. However, that’s not the case. The Earth orbits the sun in an elliptical pattern, which creates an uneven gain and loss of light. At first, we only lose a few seconds of daylight each day. The loss peaks to 2 minutes and 50 seconds during this period we’re in now. Finally, it slows to just a few seconds a day again as we get close to the winter solstice.

The sun’s angle is lower each day as we lose nearly 3 minutes of daylight

TimeandDate

The sun’s angle is lower each day as we lose nearly 3 minutes of daylight.

Bathe in the fading summer sun

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All this light loss can bring about feelings of sadness and longing for more of it but also gives us an opportunity to slow down. As the sun sets before 7 p.m. next week, we won’t feel the same sort of pressure to return to the outside after dinner as we did a couple of months ago. Mornings are certainly darker, as the sun now breaks the horizon 75 minutes later than it did in late June.

But now you can listen to a stillness that wasn’t there a few weeks ago. Birds are no longer singing at the crack of dawn, as the year-round residents call out less frequently and with totally different songs. In Chinese culture, there are actually five seasons: the four we are most familiar with, and a fifth, called late summer.

Late summer is that time when the earth is about to go into that big fall transition but still hasn’t cooled significantly. It’s a small window, from roughly late August until the final week of September when autumn begins. The season is associated with the element Earth, paying homage to the bounty of the time of year when the earth is giving us so much. Head to any farmers market, and you’ll quickly realize this is peak harvest season.

Late summer brings a wide variety of fresh produce.

Late summer brings a wide variety of fresh produce.

The berries of Ilex Verticillata have not turned red in early September.

The berries of Ilex Verticillata have not turned red in early September.

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Summer’s final days mean birds have long ago fledged but aren’t yet gathering into their winter flocks. Hummingbirds are still at our feeders, dancing in parabolic arcs with lightning precision. Nature reveals much in this fifth season, but we need to take an active role to see it. Berries, the autumnal food of choice for a plethora of fauna, aren’t fully colorful yet, but nonetheless add interest in the landscape. They’ll continue to swell a bit more each day. Migrating birds will clear many of them in coming weeks. Some will end up in holiday decorations. The deep autumn colors are a month or more away, yet there are other hues, softer and subtler to enjoy, as noontime shadows increase.

Heading into autumn

Sept. 22 is the fall equinox. On that day, we will have already lost half our potential day length and will begin the two-month period of most-rapid temperature falls. It may surprise you the loss of daily light actually slows down from a peak decrease of two minutes and 50 seconds each revolution of the planet this time of year, to about a minute and a half late in November.

Daylight Saving Time ends Nov. 5. While you’re sitting down to your Thanksgiving meal, so much daylight will have already vanished there will be only 20 more minutes to lose before reaching the yearly minimum, less than a month later.

Nature gives us a gift of change with each passing day, and you can open it with your eyes and behold the glory of this amazing natural world and its predictable annual wonders.

Follow Dave Epstein on twitter @growingwisdom.
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