"Precipitation levels" refers to the amount of water (in the form of rain, snow, sleet, or hail) that falls from the atmosphere to the ground in a specific area during a given time period. Full definition
Of course, there aren't any direct records of precipitation levels thousands of years ago. (sciencedaily.com)
The hockey stick gang assumed annual growth rings were due to temperature when most are about precipitation levels. (drtimball.com)
This lesson explores the relationship between the amount of water vapor in the atmosphere available for precipitation and actual precipitation levels. (nasawavelength.org)