What is the use of the word chilly spring to describe winter?

Cold spring describes the unusually cold weather in spring. From Songshi Puji's "Five Lantern Festival Yuan" Volume 19: "The spring is chilly, freezing young people to death."

When the spring is chilly, it is still cold and warm, and you know how warm and cold it is. It shows that the cold in winter has not completely dissipated. Winter, unwilling to be lonely and struggling, still adds a little depression to the prelude of spring, which can't open the curtain of spring.