Why did the author describe the bad weather in early spring in the north at the beginning of Man Jing's Travels?

The words "after the Flower Festival, the residual cold is still strong" and "Jude" show the cold in the early spring in the north. Then, the first paragraph tries to write about the cold in early spring in the north.

In the second paragraph, write that the weather is mild and the travel is warm. Although the wind is still strong, you will sweat when you walk. The contrast between cold and warm shows the warmth of early spring.

"I know that there is no spring in the suburbs, but people in the city don't know." This is the contrast between suburbs and cities, showing the beauty of spring outside the city.