Keep Cool in Ice Twist
It can get a bit puthery in Japan. But being Japan they have worked out how to stay smart without succumbing to the heat (or descending into the dishevelled Western indecency of flip flops and vests).
Ring Jacket (1954) of Osaka, Japan, are particularly on the case with their suits and jackets. For some they use a loose tropical weave woollen cloth (sometimes with silk) called Ice Twist. Breathable and cool, wearing Ice Twist makes you feel like a smartly-dressed piece of cucumber floating in a chilled glass of Pimms.
The quarter-lined grey suit you see here is in Ice Twist. This high-tech cloth is of Japanese manufacture, I believe, but does anyone have more gen on it?
If your local gent's outfitters or tailor can't help on Ice Twist front — the name alone seems to knock the ambient temperature down a degree or two as I type it — wander over to The Armoury, based in Honkers and New York, to see if they have anything in a tropical cloth by Ring Jacket that will fit you.
Note that The Armoury stocks an excellent selection of suits and jackets in British cloths too, as well as many of the classic names we know and love.
Refreshing Summer Tweed
With Ring Jacket you can also consider tweed in high summer. The Armoury regards the Ring Jacket sports coat below as a 'summer tweed'. Made from an open weave cloth blending wool, silk and linen, the jacket is fully-canvassed and quarter-lined.
Whatever happens promise me you won't take the vest and flip flop route if the temperature keeps heading up?