PROBLEM TO BE SOLVED: To determine the precipitation mode automatically by measuring the falling impact of precipitation onto the ground along with the outer air temperature, correcting the precipitation mode with the outer air temperature and determining the precipitation mode.
SOLUTION: Falling impact of precipitation onto the ground is measured 1 and the outer air temperature is also measured 2 and inputted to a microcomputer 3. The microcomputer 3 is previously inputted with a program for correcting 4 the precipitation previously with temperature conditions to determine 5 the precipitation mode. Precipitation is then measured 6 continuously with that mode and intensity of precipitation and an accumulated record 7 is recorded in the microcomputer 3 and analyzed before a data is outputted 8. A precipitation sensor for measuring 1 the falling impact 1 has umbrella shape, for example, and comprises an acoustic sensor or a vibration sensor for detecting precipitation impact.