Why is it summer in China and winter in America?

It's summer in China and summer in the United States, not winter.

Because both China and the United States are located in the northern hemisphere, the seasons are the same. The gradual changes of the four seasons are not uniform all over the world. It is summer in the northern hemisphere and winter in the southern hemisphere. The northern hemisphere turns from warm to cold, and the southern hemisphere turns from cold to hot.

According to the inclination of the earth's axis, winter in the northern hemisphere begins in beginning of winter in the twenty-four solar terms and ends in March 2 (about March 20). Summer begins in the long summer and ends at the vernal equinox in September (about September 2 1). The northernmost part of the northern hemisphere is the Arctic Circle, and the North Pole is the northern end of the Arctic Circle. Its seasons can be roughly divided into winter and Leng Xia is cold, and the average temperature is lower than other areas.