Let's get straight to it — here's what actually matters on this one.

• GSM (grams per square meter) measures fabric density — lower GSM means lighter, more breathable fabric; higher GSM means heavier, more structured fabric.
• For hot climates, look for 100-150 GSM cotton or linen — light enough to breathe without feeling flimsy.
• For blazers and structured pieces, 220-300+ GSM wool holds shape and drapes better, at the cost of breathability.
• GSM isn't printed on most retail tags, but 'lightweight,' 'midweight,' and 'heavyweight' labels usually map to these ranges.

The fit-and-fabric-health takeaway: Matching GSM to season and use is one of the simplest, most overlooked ways to solve a comfort problem without changing fit at all.

Next up: check out our guide on why does my shirt collar feel tighter after washing.