Summer is the worst season, no denying that summer is 3 months of hell with nothing but suffering. Okay, that's slightly dramatic but summer is hot and boring, you sit around and watch everyone have fun but you don't need other people to have fun. Here's my advice.
1: find a fun video game.
try to 100% it gives you a fun goal to complete. I recommend Spiritfarer. The characters are amazing.
2: sleep a lot.
Can't be bored if you're asleep.
3: find a book series you like.
Tbh, I don't really like reading but if you find a book your interested in it can be fun. i recommend a longer series then you don't have to find a new book which for me is the hardest part along with starting just try and read the first three chapters.
4: Halloween.
While you lay in a puddle of your own sweat, put on a fall playlist and go onto Pinterest or any other site like that to find some costume ideas or jack ‘o’ lantern ones.
5: find a good show
Just find one you like and watch a few episodes a day or don't sleep and binge it in one night.
6: learn a new hobby
Learn an instrument, skateboard writing. Idk.
7: start a big project.
Write a book, make a game, start a webcomic. Something big gives you something to work on.
8: explore.
Get on a bike and go somewhere, climb a tree and find something cool.
9: lay on the ground.
10: stay somewhat connected to society.
Just text someone at least once a week to remind people your not dead.
11: try baking
Make something tasty. Eat it.
12: draw.
Try and get better at making characters, there are plenty of online drawing challenges.