Why is it so cold in April now?

The reason why it is still cold in April is that it is cold in late spring, that is to say, in the process of warming up in spring, the weather temperature is obviously reduced due to the invasion of cold air.

It is mainly caused by long-term rainy weather or frequent invasion of cold air, or by strong radiation cooling in sunny nights under the control of cold anticyclone. If the average temperature in late spring is more than 2℃ lower than normal, it is considered as cold weather in late spring, which can cause harm to agricultural production, especially in the early stage of late spring, which is higher than normal, and in the later stage, the temperature is lower.

standard

The late spring cold mainly refers to the weather phenomenon that the average temperature drops below the same period of normal years and lasts for a period of time under the background that the temperature generally rises due to the influence of frequent cold air going south in the north or continuous rain in the south every spring (March-May) in China.

As for the extent and duration of cooling, local standards are slightly different. For the northern region, the cold spring means that the cold air force is enhanced and the temperature drops sharply; For the southern region, it is usually associated with low temperature and rainy weather.

Agrometeorological experiments show that the average daily temperature is less than12℃ and the maintenance period is more than 3 days, which is not conducive to seedling growth. If the cooling is accompanied by rainy weather, the harm will be even greater, which is a relatively recognized indicator. In southern China, the spring sowing time comes first and then comes, and the period and intensity index of the cold spring are also slightly different.

For example, Guangdong refers to the low temperature below the middle and late March in central and southern Guangdong as late spring cold: the daily average temperature is ≤ 10~ 12℃ for 3~4 days or more; Daily average temperature ≤ 15℃, sunshine ≤2 hours, continuous 7 days or more. ?

China has a vast territory, different weather and climate conditions and different victims, so the standards of meteorological disasters will be different.