Wool is the most popular fabric choice when it comes to making suits.
One important quality is that wool "breaths". Wool is woven thus allow air to move through and moisture to evaporate, keeping you comfortable during mid-days and cool nights.
Wool is also naturally dirt, flame and water-resistant. This makes suits made from wool easy to care as they do not require cleaning after every use.
Wool can also absorb 30% of its weight in moisture without feeling damp, whereas cotton can only absorb 8%.
Wool is very durable as it resists wear and tear and can easily recover back to its shape, making it a great fabric with good wrinkle-resistant property.