in Thoreau’s Journal:

This is the end of the sixth day of glorious weather, which I am tempted to call the finest of the year, so bright and serene the air and such a sheen from the earth, so brilliant the foliage, so pleasantly warm (except, perhaps, this day, which is cooler), too warm for a thick coat — yet not sultry nor oppressive — so ripe the season and our thoughts. Certainly these are the most brilliant days in the year, ushered in, perhaps, by a frosty morning, as this. As a dewy morning in the summer compared with a parched and sultry, languid one, so a frosty morning at this season compared with a merely dry or foggy one. These days you may say the year is ripened like a fruit by frost, and puts on brilliant tints of maturity but not yet of decay. It is not sere and withered as in November. See the heaps of apples in the fields and at the cider-mill, of pumpkins in the fields, and the stacks of cornstalks and the standing corn. Such is the season.