My city is very hot, I want to go to the Waterpark or water pool.
But, I'm summer vacation going to the pool.
Here's your corrected composition, Jimmy. Please take a look at the corrections below. Have a good evening there! 
Describe the summer season in your city.
My city is very hot, I want to go to the Waterpark or water pool.
But, I'm summer vacation going to the pool.
>>> It's really hot in my city, so I want to go to a water park or pool. Luckily, I'm planning to visit the pool during summer vacation.
>>> OR: With the heat in my city, Id love to cool off at a water park or swimming pool. Good thing Ive got a pool trip planned for summer break.