In some places it never cools down. I used my Gunn-worn concealed carry GIBSON VENTILATOR mesh back vest when I traveled throughout the tropics in south east Asia. This time I wasn't carrying, but, the vest worked brilliantly as a travel vest. I was able to hide my phone, wallet, passport, reading glasses, a bottle of water, map and a heap of other stuff. I never needed to take a bag when I went out for the day.