Rainfall (mm) is the height of rainwater that collects in a rain gauge on a flat place, does not absorb, does not seep and does not flow. One millimeter of rain means that rainwater that falls on an area of one square meter will have a height of one millimeter if the rainwater does not seep, flow, or evaporate. Rainfall is the amount of rainwater that falls on an area in a certain time. Tool to measure the amount of rainfall is called Rain gauge. Rainfall is measured in daily, monthly and yearly terms. Rain is the event of the arrival of water in liquid or solid form which is poured from the atmosphere to the earth's surface. Rainfall measurement can be done with the help of a device called an ombrometer. The rain gauge is a device for measuring the amount of rainfall that falls on a scale per unit area. The principle and workings of this tool is to measure the height of the amount of water that is stored or stagnant.
Rainfall that exceeds normal limits can trigger wet hydrometeorological disasters such as floods, flash floods and landslides.