China's agrometeorological disasters online map of continuous rain frequency during wheat harvest time in North China was derived from the National Agricultural Atlas of the People's Republic of China.

For three consecutive days, the daily sunshine is ≦6 hours, the total amount of precipitation is 20 mm, or the daily sunshine is >6 hours. There is precipitation every day and the total amount is 20 mm for one continuous rain, which is expressed by frequency. Wheat harvest period: I. June 11-25 II. June 1-15 III. May 22-June 5.