I'd have to say Kouros Fraicheur if you could find it or mind paying the price on ebay for a rare 100ml bottle of it. (I picked up a few mini bottles of 10ml for cheap; hard to find though too.) Nice breezy twist on Kouros excellent for hot weather I think.
Kouros Tattoo is a great suggestion.. Heck all the Kouros flankers I've tried besides Kouros Eau De Sport (sadly rare but ridiculously good) I'd say are great as a summer scent.
M7 Fresh isn't a bad suggestion either.. be nice for a day out that turns into a warm summer evening. And hey cant go wrong with the classic Pour Homme.. Rive gauche I could see being used well in warm weather to; maybe a more mild day though for me.
The L'Homme series I'd say also is a good summer scent.. I'm a huge classic YSL fan but I still like and own these scents even if they are 'safe'. Of good quality and still have very individual characteristics once you really wear and get to know them IMO.
Strange Live Jazz dose not last for you! Its funny I wore it today for a 10 hour shift at work and was surprised I could still smell it after.. usually freshen up with a 2nd scent after the work day but didn't need to. (..Still did though have so many samples I wanted to try
See YSL does have a lot to offer for summer!