As of the end of May, the Great Miami River Watershed received 18.01 inches of precipitation this year - that is 0.43 inches below average for this point in the calendar year. An average of 2.52 inches of precipitation fell in May to the Great Miami River Watershed. That is 1.96 inches below average for the month. We track precipitation to help us understand water quantity trends and long-term conditions. You can do a deep dive on all the data we collect here.