The relevant analysis data shows that 70% of hail time in most areas of
our country is concentrated at 13:00 to 19:00, especially at the time of
14:00 to 16:00. In the western parts of Hunan province, Hubei province,
and Sichuan Basin, hail often occurs at night. As for some other places,
such as the Qinghai-Tibet Plateau, there are mostly hailstorms at noon.
In addition, there are some obvious monthly changes of hail in China,
which is in accord with the monthly change of atmospheric circulation
and monsoon climate: the hail area would move northward if the southern branch
jet stream does so, and the hail comes almost one month earlier than monsoon
in each area.
In most cases, Fujian province, Guangdong province,
Guangxi province, Hainan province and Taiwan have hailstorms from March to April;
Jiangxi province, Zhejiang province, Jiangsu province and Shanghai
have them from March to August; Hunan province, Guizhou province,
Yunnan province and some areas in Xinjiang experience hail from April to May;
most areas of Qinling Mountains and Huaihe River have hails from April to August;
North China and some areas of Tibet suffer hail from May to September;
Shanxi province, Shanxi province, Ningxia province have them from June to August;
most areas in the northern of China has hails from June to July;
The Qinghai Xizang Plateau and some other high mountain areas suffer hails
from June to September, where often have “Hail month”. In addition,
since there is a very strong local feature of hail in China, the inter-annual
changes in various regions and even the whole country are very large.
There are several characteristics about hail:
1.It happens in local area. The incidence of the hail is from dozens of meters
to thousands in width and from hundreds of meters to dozens of thousands in length.
2.Its last time is of brevity. The actual period of hail lasts 2 to 10 minutes,
only very few will last more than 30 minutes.
3.It happens easily. The occurrence of hail is affected by topography.
The more complex the topography is, the earlier hail will happen.
4.It changed a lot year by year and place by place. In the same place,
there may happen several hails in one year, while in another year,
it may nearly not occur.
5.It can happen in a wide range. Hails can occur in a wide climate zone
from subtropics to temperate climate, mainly in temperate climate.