Here is the corrected version of the text: It's already fall, the most beautiful season of the year. When you think about fall, what comes to your mind first? Is it that a lot of leaves turn red or yellow and eventually fall off the trees, or walking on a street on a chilly morning? Both of these don't happen in early fall. I know that many people have been struggling with the hot weather for many months. They look forward to autumn, but as autumn comes, they find that the temperature rises to a higher level than they expected. In China, we have a special phrase to describe this weather. We call it "Autumn Tiger." The heat outside is just like a tiger which comes in a rush but exceeds people's expectations. The worst thing is that it gives people both physical and mental discomfort. The good news is that the "tiger" will also go away in a rush. About 15 days later, true fall will come with a high blue sky and fresh air.

Many of my changes are just question of style. I hope this is helpful.