I realise this is not entirely based on artistic styles, seiyuus or critics, etc. but please bear with me.
Which anime gives you the greaatest summer feeling?
In my case, I have two answers.
Barakamon, a man who lived his whole life in the city is forced to move to an island, where he gets to know a completely new world of human interaction. The villagers help him and seem like one big family, giving this show a really positive ambience. Of course, the summer feeling isn't being neglected.
Nagi no Asukara, people were seperated into those living in the sea and those dwelling on land. Interaction between those two groups is kept to a minimum, but of course, the high schoolers break those rules, albeit not peaceful at first. Despite the overwhelming twist after the first half of the show, it is still one of my favourites since I watched it on a boat while sailing the seas of croatia. This trip was full of first experiences for me, having a friend to talk to, meeting a cliche and easy-going captain and sitting on one of the hulks of a catamaran during a storm, I can really recommend a sailing tour!

So, which anime gets you in the best summer mood and why?
Did you make similar experiences connecting a show and a season?