If the weather is nice then surely a sun hat and no clothing on the upper body is required, just a bit of sun cream, I of course acknowledge that some may find this an embarrassing look but frankly how some people look WITH clothes on can be quite disturbing
I wouldn't give more than a cursory glance at someone on a bike with no top on man or woman (or any other mode tbh), in fact I'd think how great it was that they could go about where they wanted without pandering to some faux society norm.
Personally I wear a pair of nice lightweight walking shorts during the summer and with open and zipped pockets on the hip and a zipped pocket behind it's plenty for keys/change and a wallet or phone without interfering with ones pedalling action.
Sometimes I wear jeans or corduroy/canvas type trousers which I find pleasant enough in warmer conditions, in lieu of a trouser clip it's no big deal to roll the leg up on one side (or both if you're into the symmetry look
Top wise I'd rather wear a thin cycling jersey then quickly change into another top, I've arrived at meetings in 3/4 length winter bibs and just carried on as normal, other people need to stop thinking what one wears is important or has any bearing on you as an individual.