I thought you were only talking about the Eucharist. Obviously, in choir dress the cassock is quite necessary. It sounds horrendous. I have lived where the temperature is higher but the humidity low. It was far from pleasant but more bearable. The humidity just makes life intolerable for me. I once spent a time in the tropics. It was an absolutely miserable time for me unless I was near air conditioning and had a large glass of cold water in hand.