Where did the rain gauge originate?

One source has is that the son of King Sejong the Great, who reigned during the longest imperial reign, the Korean Choson Dynasty from 1392-1910, invented the first rain gauge.

King Sejong sought ways to improve agricultural technology to provide his subjects with adequate food and clothing. In improving agricultural technology, Sejong contributed to the sciences of astronomy and meteorology. He invented a calendar for the Korean people and ordered the development of accurate clocks. Droughts plagued the kingdom and King Sejong directed every village to measure the amount of rainfall.

His son, the crown prince, later called King Munjong, invented a rain gauge while measuring rainfall at the palace. Munjong decided that instead of digging into the earth to check rain levels, it would be better to use a standardized container. King Sejong sent a rain gauge to every village, and they were used as an official tool to measure the farmer's potential harvest. Sejong also used these measurements to determine what the farmer's land taxes should be. The rain gauge was invented in the fourth month of 1441. The invention of the rain gauge in Korea came two hundred years before inventor Christopher Wren created a rain gauge (tipping bucket rain gauge circa 1662) in Europe.

(Click the tipping bucket drawing to observe the action of the device.)

Using rain gauge measurements

Light rainfall is less than 0.10 inches per hour, moderate rainfall measures 0.10 to 0.30 inches of rain per hour, while heavy rainfall is more than 0.30 inches of rain per hour.

One inch of rainfall produces 4.7 gallons of water per square yard or 22,650 gallons of water per acre!

How to use a rain gauge

Rain gauges should be placed in an open area where there are no obstructions, such as buildings or trees, to block the rain. This is also to prevent the water collected on the roofs of buildings or the leaves of trees from dripping into the rain gauge after a rain, resulting in inaccurate readings.

Measuring precipitation as a hobby - CoCoRaHS

CoCoRaHS is an acronym for the Community Collaborative Rain, Hail and Snow Network. CoCoRaHS is a unique, non-profit, community-based network of volunteers of all ages and backgrounds working together to measure and map precipitation (rain, hail and snow). By using low-cost measurement tools, stressing training and education, and utilizing an interactive website, the organization's aim is to provide the highest quality data for natural resource, education and research applications. CoCoRaHS has participants in all 50 states.