It’s almost July and this means one thing in the Boreal hemisphere: heat. This only means one thing: it’s time for summer suitings! This is actually a question I got from my friend Nayila the other day, and I was quite frankly shocked I’ve never done a post before, given that summer here is incredibly hot and the warm season quite prolonged.
Generally speaking, summer makes everything more casual, and that includes when it comes to wearing suits. More than anything, weave is important: the main point is to maximize air flow, so opt for loosely woven fabrics. A common misconception, for example, is using high super number fabrics (more on the “super” here) as those fabrics tend to be lighter in weight. High super number textiles are, however, very tightly woven, and therefore not an optimal choice for summer. The same applies for shirts: in my opinion one should steer clear of fine cotton shirtings which are very dense, instead opting for linen blends and looser weaves.
So without further ado, here is a list of fabrics for warmer climates.
The wools
Contrary to popular belief, wool is an excellent choice for summer: its temperature regulation properties as well as moisture wicking capabilities make it a good choice for even the stickiest day in Tokyo.
Weave-wise, opt for example for a Fresco. This fabric was originally developed by J. & J. Minnis, but you can now find similar fabrics produced by many weavers under various names. The key point is that all of these fabrics use a high-twist yarn, and so give a textile with a dry hand. The high twist yarn paired with the loose weave make it a great choice for summer.
Fun facts about Fresco: J. & J. Minnis apparently patented it in 1907, and in the patent application the manufacturer explained that, in a worsted cloth woven with the ordinary double or single threads, the threads were liable to flatten under pressure, closing up the small interstitial openings left in weaving (which would result in a “close weave”). However, “according to this invention, we twist together a double and a single yarn, producing thereby a thread for both warp and weft which, when woven into cloth, retains its roundness while the cloth is in wear, and we thus prevent the closing of the said openings and attain the said object”. This explains how Fresco is very crisp and stands away from the body, making is such a good summer fabric. It’s also ideal as a travel suit because it is wrinkle resistant. The current Fresco range arches from 250 grams in weight to just under 500 grams.
Last, because of the open weave, often Fresco solids have a “mottled” appearance, which camouflages the openness of the cloth.
Alternatively, you can go for any wool labeled as Tropical. These are fabrics designed for hot climates, and come in a variety of shapes and forms although they may or may not use a high twist yarn. Often, they are simply very light weight worsted fabrics. The main advantage is that they are very readily available and generally cheaper than Fresco.
Another wool option which I love is Hopsack, but I am probably biased as I just got a good 5 meters of it in the Rubinacci archive fabric sale. Hopsack (which is actually a weave, not a fabric type) is characterized by a very airy and open weave basically similar to a basket weave and is coarse-feeling, breezy and fresh.

The linens
It is no mystery that linen is probably the favorite fiber of the sewing IG universe. Linen was one of the first fibers to be domesticated by humans, and still one of the most used for anything from suits to tablecloths. It draws heat away from the body, keeping you cooler in the warmer months. Linen is a very long fiber which makes it very hard wearing and resistant to abrasion, maintaining its strength also when wet. Fun fact! Silk, the strongest among natural fibers, looses this property when wet.

Generally speaking, Irish linens are more stiff but take a crease very well, whereas Italian (and, in my experience, most Japanese) lines are softer, so keep this in mind if you are making a linen suit. So far I’ve made two (one in Japanese linen from Niigata, another one in Irish linen) and I thoroughly enjoy them in summer. It’s not as easy to tailor as wool, because it doesn’t shrink with steam and therefore needs careful cutting as well as strategic sewing. Linen wrinkles like there was no tomorrow, but I do enjoy that aspect very much: there’s something about the way the wrinkles lay which doesn’t say “wrinkled mess”: it says “I’m cool and fresh too!”. Also: don’t forget the low environmental impact of linen.
The cottons
Personally, I don’t think cotton is the best option for a suit, because its fibers are not as resistant to abrasion as other fibers. However, Seersucker is a popular summer option. This weave is achieved by warp threads for the puckered bands being fed at a greater rate than the warp threads of the smooth stripes. This feature causes the fabric to be mostly held away from the skin when worn, facilitating heat dissipation and air circulation, making it a great summer option.

This is it! Hope you enjoyed this brief guide. Happy sewing.
I had no idea wool could be worn in summer! The part about the yarns in the weave itself explains why I’ve always found cotton shirtings to feel stifling in the summer even when wearing a looser fitting shirt… *the more you know*