It’s not easy wearing a jacket in the summer. Even if there’s air conditioning in your home/office/restaurant, it often feels too hot to wear anything as encompassing as a jacket outside and feels a little silly to only put the jacket on when you’re inside.
I should point out, though, that in my experience it is worth persisting for a couple of weeks as the temperature creeps up. Anyone can wear a jacket, particularly a lightweight one, for longer than they think, or rather in higher temperatures than they think. Don’t torture yourself; but do set your tolerance levels a little bit higher. Wearing a jacket will always look more elegant than not doing so – it is the sartorial centrepoint of any wardrobe and any outfit – and a man with any interest in clothes will find it more enjoyable to have it as an expressive outlet.
As mentioned in passing in that previous paragraph, the jacket in question should be lightweight. It should also be only partially lined. Finally, it helps if it is of an open weave.
To start with the first of those points. The weight of the wool used for the jacket is crucial – aim for something like 9 or 10 ounces. That should feel very easy and flighty to wear, while not wrinkling too easily or wearing out at the elbows in a matter of weeks. I purposefully said ‘wool’ for that weight, because with other summer cloths like cotton or linen, you can get away with something heavier. Indeed, you should seek it out.
For linen is more finely, openly woven (touching on the last of these three points) and therefore lets in air between its fibres – creating the ‘wicking’ effect that so many hiking retailers market to you incessantly (it just means having small holes that let in a little air which, running across the surface of the skin, helps sweat evaporate). So you can pick a 12 or 13 ounce linen without any problems, and it will crease far less than a lighter linen – avoiding that ‘I just pulled this out of the laundry basket’ look that often comes with a linen suit.
While we’re on the subject of weaves, to pick up the third of my points, there are many wool options that will be cooler than their weight suggests because of the looser way they are woven. Basket weave is a good example – thicker threads are more loosely bound together to allow air to move through them. It’s easy to spot because of the way you can see the weave in the wool when you look at it. Indeed, most cloths where you can easily see the threads themselves and how they are woven will be an open weave. Other good examples are Minnis’s Fresco and Smith’s Finmeresco – the former is often used as a generic term to refer to all these open-weave wools.
Finally, make sure the jacket is unlined or only partially lined. I’ve written about this before so no need to go into details, but I would say again that if you are concerned at all about a linen suit being as smart as possible, go for a half lining at least. At least then the front parts are less likely to wrinkle.