the weather is cooler in Qingdao than

网友回答

因为外国人讲话也是不忌讳重复,原句应该是
the weather is cooler in Qingdao than the weather in Wuhan
但是这样很累赘,所以用that代替了the weather
这种用法在含有 than 的表示比较的句子中很常用的
======以下答案可供参考======
供参考答案1:
that,此处 = the weather
供参考答案2:
that 代表前句当中的 weather,也就是青岛当地的天气。