Heat getting to stored tea?

I packed all of my tea with me to go up to college, and my car broke down, and I had to wait with it in a packed car in 75-80 degree weather for three ours to get it towed. It was in a cardboard box, and most of the teas I’ve had are fine, and the taste is slightly off. I’m probably worrying too much, or it could have been the way I brewed it, but just in case, I want to know how drastically these conditions can damage the leaves.