It’s hard to explain, but these either are good to watch on a hot summer night or have sceneries that evoke a hot summer night.

Evangelion and End of Evangelion

Chainsaw Man

Fullmetal Alchemist

Bocchi the Rock

Perfect Blue

Your Name

Spy x Family

The Tatami Galaxy

Nana

Madoka Magica

Summertime Render

Higurashi When They Cry is the first thing that comes to mind for me when I think of summer heat, nights and screaming cicadas

Steins;Gate one of the very characters itself is the hot oppressing city and there is this constant sound of cicadas in so many shots that keep this feeling of summer throughout all while being a really really good character piece of what insanity looks like.

I also really love Anohana but thats more about nostalgia and making me cry.

Call of the Night - the whole show is just pure vibes, and it portrays the nighttime in a unique way. Watching it after it gets dark enhances the experience. It’s even better if you have a thing for vampires

Besides the obvious “summer” theming, I really liked The Summer Hikaru Died for being one of the only horror manga to still be good once made into an anime.

Nagi no Asu kara has that refreshing sea theme.

I discovered Inuyasha only because I find it hard to sleep when its hot and it would play on Adult Swim at like 2am. The filler episodes are usually chill, and there are a lot of them. My favorites are the ones focused on Shippo.

It’s winter for me at the moment but I adore Call of the Night for the wild midnight vibes and also Insomniacs after Dark cause it’s cozy as.

Kowloon…

It’s a nice, misterious anime with old style anime style. Has a strong summer vibe