Why is it so cold in spring?

This is what people often call "cold spring".

In the four seasons of the year, the season with the greatest changes in meteorological elements such as temperature, airflow and air pressure is spring. It is often sunny during the day, which makes people feel "warm wind makes tourists drunk", but it is chilly in the morning and evening, which makes people feel "chilly in spring". This unpredictable "fickle" weather is commonly known as "cold spring".

Usually, people will take March as the beginning of spring. The biggest feature of spring climate is that it is warm first and then cold: first, the temperature difference between day and night in spring is large; Second, there are frequent cold air activities and more weather changes in spring. In meteorology, "late spring cold" originated from agriculture at the earliest, which mainly refers to real spring, that is, in a climate, the average temperature exceeds 10℃, and the temperature drops rapidly due to frequent attacks of strong cold air, lasting for more than 1-2 weeks, and causing large-scale freezing of crops.