Why is the temperature difference too big recently?

Late spring cold (English) refers to the weather phenomenon that the temperature rises rapidly in early spring (generally refers to the end of February and the beginning of March) and the temperature in late spring cold (generally refers to April) is lower than normal. Long-term rainy weather or frequent cold air intrusion, or under the control of continuous cold and high pressure, strong radiation cooling in sunny nights is easy to cause late spring cold. The climate is changeable in early spring. If the cold air is strong, the temperature can drop to below 10℃, even in rainy and snowy weather. At this time, it is often sunny during the day, which makes people feel that "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 what is commonly called "cold spring". It is easy to adversely affect agricultural production and residents' lives.