Why does the running speed drop in winter?

First of all, the weather temperature is relatively low, and the warm-up time of running is longer than that of summer, which reduces the running speed.

Secondly, when the weather is cold, some calories will be lost during breathing, which will increase the running burden and reduce the speed and distance.

Finally, wear more clothes in winter than in summer, so the resistance will be greater when running, so the speed will slow down.