It's still hot in Tokyo during the day. But in the early morning and late night it gets kinda kinda cool. You'd be fine with just a t-shirt but you could put another shirt on and it wouldn't make you sweat. So you want to put one on. The most practical option might be a button front shirt. But it's kind of boring isn't it? so the other option is a loose fit (or big size) long sleeve T-shirt. You can just pull it over your head. You don't need to worry about whether to put buttons on, have it open, roll up sleeves, tuck it in or not and stuff. It's got a good roughness in the big size long sleeve T-shirt style. Oh and it goes well with shorts. Look loose and be sharp.
東京はまだ暑い。でも夜になるとちょいっとだけ涼しいような気がしないでもない。Tシャツ1枚でも平気だけど、もう1枚上に着ても汗だらーっとはならないぐらい。だったら着たい、そんなあなたはおしゃれ好き。何着よう、シャツ着よう。えー!普通。ロンT着よう、おっきめの。さらっと。ゆるっと。かぶるだけ。シャツだと色々着方がオプションありすぎて面倒だ。ボタンいっぱいあるし。ゆるロンTはショーツにバツチリ合うだ。これであなたもゆるキャラだ。