Sartorially speaking, this shoulder of the shoulder season should evoke the subcontinent more than our own native tribes. While its typically brighter incarnations are best reserved for carefree summertime, Indian madras is also loomed in more subdued colors -- rust reds, chocolate browns, burnt oranges, and moss greens -- more suited to a more suited season. Such schemes work particularly well as ties (which start working their way back around necks this time of year), contributing bold patterns to autumn’s more muted outfits. As always, an excess of Earth-toned richness can be cut with a spot of oxford cloth in light blue (or any other pastel shade you’re not quite ready to retire for the year).
This is also the time to actually wear all those "summer" sportcoats you’ve been carrying over your arm and leaving on your chair for the past few months. Chunky linen, sleek gabardine, and slubby silk jackets actually cool when worn in less apocalyptic temperatures. Set them up with cream trousers or white bucks (not both; that time has passed for now) as a jaunty nod to the departing season, or with tropical greys and brown suede if you can’t wait for the first frost.
Socks. You really should put them back on. I’m more indulgent of bare ankles than most traditionalists on this matter, and have myself enjoyed their cooling efficiency on real steamers, but once Labor Day rolls around, it’s best to stow the invisible hosiery in your invisible yacht, or else they won’t feel so transgressively liberating next spring.
Finally, the September 15th cutoff for wearing panamas and boaters should be absolutely respected in observance of the infamous 1922 Straw Hat Riot. The Youth are still lurking everywhere, and given what those things cost these days, one cannot be too careful.