A crew-neck t-shirt and white vertical striped shorts are an urban combo that every modern guy should have in his wardrobe. Bump up the dressiness of your outfit a bit by slipping into boat shoes. This getup is a safe option if you're on the lookout for a great, season-appropriate getup. Now that's how you dress casually as a man in his 30s.
For a relaxed casual look with a modern finish, consider pairing a crew-neck t-shirt with navy chinos. Add boat shoes to this outfit and the whole look will come together quite nicely. You totally can keep your cool under the oppressive heat. The proof is right here Gents who wonder how to wear modern casual dressing as you get into your 30s, this getup should answer your question.