Double rainbow
A double rainbow is the same sunlight bouncing twice inside the raindrops, which is why the outer bow is fainter and its colors run in reverse. The darker band of sky between the two arcs has its own story to tell.
What it may mean
Look closely at a double rainbow and three things stand out. The second arc is higher and fainter. Its colors run the other way, with red on the inside instead of the outside. And the strip of sky between the two bows is darker than the sky inside the first or outside the second. That strip is called Alexander's band, after Alexander of Aphrodisias, a Greek philosopher who described it around 200 AD. It is not a shadow; it is the zone where neither bow sends light toward your eye. Between two bright arcs sits a dim gap, made by the same sunlight. Life has its own dim gaps, too: the quieter, duller stretches between two good seasons, such as the months between jobs or the lull after one celebration and before the next. They belong to the same weather.
Depending on how you saw it
The outer bow with its colors reversed
In the outer arc, red sits on the inside and violet on the outside, the reverse of the main bow, because the light took one more bounce inside each drop. What have you understood better the second time around, once you saw it from the other side?
Only part of a second arc
Often the outer bow shows only in pieces, a bright stub at one end and nothing above. Its light is weaker, so it fades first where the rain thins out. Which good thing in your week is only half visible and still worth pointing out to someone?
Strangers stopping to look
A double rainbow often makes strangers stop, point and talk to each other in parking lots and on sidewalks. A rare sight wants to be shared. Who was the last person you called outside to see something, and who would you call next time?
Why it happens in nature
Light that bounces once inside each raindrop makes the main bow; light that bounces twice makes the fainter outer bow, which sits higher in the sky with its colors in reverse order. The sky between them looks darker because neither path sends light toward you from that zone, a strip known as Alexander's band.
To reflect on
Which dull in-between weeks have you been treating as wasted time?