What kind of weather changes do we often say "cold in spring"?

Late spring cold, weather phenomenon. According to the Meteorological Index of Late Spring Cold (GB/T 34816-20 17) formulated in 2017, the meteorological late spring cold refers to the phenomenon that it is warm in the early spring, cold in the late spring and the temperature in the late spring is obviously lower than normal.

Harm of late spring cold to agricultural production

Late spring cold is a very serious forestry and agro-meteorological disaster, which refers to the weather and climate phenomenon that the temperature drops rapidly in spring due to frequent attacks of strong cold air, resulting in continuous freezing damage to trees and crops in a large area.

Late spring cold often causes rotten seeds of peanuts, vegetables, cotton and wheat in northern China, and also affects the emergence and growth of rice in southern China, which brings serious harm to agricultural and forestry production.