Sharply-defined mountains against an achingly blue sky; sunlight filtering through the remaining golden leaves...it's Frederick* weather.
If you missed Frederick by Leo Leonni as a child, quick go buy it used on Amazon (or, strangely, new in Spanish), before the weather changes. While all the other fieldmice gather grain and nuts, Frederick sits peacefully on the wall, doing his own kind of gathering. Then the mice take to the wall for winter. When the food stores dwindle and the stones grow cold, Frederick brings out the memories and feelings he stored on the stone wall in the sunshine.
Days like today make me want to harvest sunshine, before it crinkles up and blows away.
*And, um, if anyone from the FTC is looking for full disclosure, no one gave me a copy of this book. My sister got it for her birthday when she was three, and she let me read it. A lot. I got Swimmy, which is also fabulous, but not necessarily for a fall day. I was four. I accidentally found Frederick in my possession for a while, but gave it back when I was 32. Or possibly 38. The last fifteen years are kind of a blur, and full documentation was not maintained.