Is it ok to leave items in the trunk of a car?

I drive a 1999 Honda Civic and i was wondering is it okay to leave items like washer fluid or a case of water or anyone items (other than food) in the trunk. I do not have windows where you can see the trunk but i leave it outside of my house since there's no room in the garage and usually the temperature is around 20 degrees Celsius during the summer. Will it go bad or i should be fine?

It's fine

Bodies no, water and washer fluid yes.

Yeah it is completely fine to do so, that's actually a smart thing to do if you need brake fluid or transmission fluid or windshield wiper fluid etc.

Bottled drinkable water should not be stored in the car, especially not during the summer or warm days. The plastic can break down and leech into the water. Hot/cold may also help to grow bacteria that can make you sick. Brake fluid, oil and other flammables should also not be stored in the trunk of the vehicle.