Short Sleeve Pullover Sweater
This short-sleeved version is ideal for truly hot weather, but 3/4 and long sleeves are typically bearable in all but the hottest weather. .... might not work with broiling weather, but for slightly warmer days: dress/tunic over leggins/pants, a camisole underneath a (short sleeved) blazer or cardigan, these breezy little cotton sweaters they sell everywhere now over a longer blouse etc.
