The heat brings discomfort, but this doesn't mean that sartorial excellence has to go out of the window. I don't have a smart summer suit and am on the lookout for one. Here are some images that inspire me in my search for the elusive ideal suit.

If you own the rights to any of the above images and would like them removed, please get in touch.
Linen, cotton, lightweight wool, silk, or a combination of these, make the best cool cloths. I like the crumpled, comfortable, casual style of linen and would look for pale blue or cream/tan as the most classic and practical colours. Wear with a linen or seersucker shirt; no tie, or with a cotton floral tie and a silk or cotton pocket square in pale, sunny hues.
Make sure the suit fits properly, snug across the shoulders and the correct length in arm and leg. Have the suit altered if it's not too far out; there are alterations tailors on most high streets. If it's too far out in sizing, alterations won't succeed, so don't buy.
Here are some of the places I will try for my summer suit (if you're quick you may find something in the summer sales):
For off the peg:
Or for made to measure or bespoke:
Edit Suits (affordable)
Hirsch Tailoring (bespoke)
Susannah Hall, Tailor (bespoke)