Watching the Sunset -- looking east

My apartment windows look almost due east.  I have beautiful dawns, especially in the winter when they are late enough that I very rarely am asleep when they flame the sky. 

I have, especially in the summer, but all year round, wonderful sunsets to watch from my windows.  As I type the sky ranges from mauve to pink to light blue with sweepings of slate blue clouds just above the trees. The clouds seem to have been pushed there from the harbor that is less than two miles to the south.  I don't know what the west-looking apartments are seeing in the sunset but I am very happy with my view.

Last night the last ten or fifteen minutes of light was astonishing.  The whole day had been rainy, the clouds were sometimes a nice dove gray and sometimes a sootier gray; the rain was intermittent although the air was full of moisture all day.  In the evening the sky turned slatey and then tried to be sincerely blue, but was not at all the watery late day light with gold in it that we get when the day has been clear. Then it slowly turned the pinky-mauve and, as I didn't look up for three or four minutes from the computer screen, I became aware of a brightness.  The sky had become a pinky biscuit that reflectied light toward me--a color I had never seen at sunset before. 

Then I saw the arch -- the rainbow which was far more awesome than in the photo that my not at all accurate camera caught in the picture above.  I went outside where I could see the whole eastern sky. The rainbow started at the far north and arched perfectly, and  very high. into the sky, all the way to the southern horizon.  It was perfect! An exact half circle. It stood there, like a computer painting too perfect to believe except I was seeing with my own eyes.  In about ten minutes the light was leeched out of the sky erasing the bottom of the arc.  Rather quickly the bow disappeared, the sky became wholly slate blue and then deep, almost night blue. 

If my windows faced west I would have missed that sunset rainbow.