What is the basis of light rain, moderate rain or heavy rain in the weather forecast?

When we listen to or watch the weather forecast, we often hear terms such as "light rain", "moderate rain" and "moderate to heavy rain", which is the grade of rainfall. Rainfall means that the rainwater falling on the ground is not evaporated, infiltrated and lost, but is determined by the depth of accumulation. The unit of depth stipulated in our country is millimeter. The level of rainfall is divided into light rain, moderate rain, heavy rain, heavy rain, heavy rain and torrential rain according to the rainfall within 24 hours. Light rain: the rainfall is less than10mm, and the raindrops are clear, which is debatable. When they fall on the roof tiles and hard ground, they will not splash, and the rain will be gentle and intermittent; It usually takes two minutes to completely wet the slate and roof tiles, and the puddle is slowly formed. Moderate rain: the rainfall is between ten and twenty-five millimeters, and the rustling rain can be heard. Rain falls like a line, and raindrops are not easy to distinguish. They splashed gently on the holes and hard ground, and puddles soon formed. Heavy rain: the rainfall is between 25 and 50 mm. When it rains heavily, the rain falls like a downpour, dripping on the roof tiles and hard ground, splashing several inches. The rain is like a drum, and the pool is quickly formed. Heavy rain: the rainfall is between 50- 100 mm, and there is water on the road surface. Rainfall between 100 mm and 200 mm is called rainstorm; Rainfall exceeding 200 mm is called rainstorm, and low-lying areas are flooded. Shower: refers to stratum precipitation, with heavy raindrops and drastic changes in intensity. When it rains, it is dark, sometimes it suddenly clears up, revealing sunny days, and sometimes it is accompanied by thunder.

According to the regulations of China Meteorological Bureau, the rainfall within 24 hours is called daily rainfall. Any daily rainfall below10mm is called light rain,10.0 ~ 24.9mm is moderate rain, 25.0 ~ 49.9mm is heavy rain, 50.0 ~ 99.9mm is rainstorm, and100.0 ~ 250.0mm is rainstorm.