Can the annual average rainfall in the Ring of Fire be measured?

The Ring of Fire is a large, horse-shoe shaped band that circumscribes a large area of the Pacific Ocean. The area contains 452 volcanoes and is known for its high number of earthquakes and volcanic eruptions. The Ring of Fire is home to more than 75% of the world's volcanoes.

From one end of the Ring of Fire to the other is approximately 25,000 miles, and as such, the climate (and thus the annual precipitation) varies greatly throughout its different parts. It reaches as far north as the Aleutian Strait, and as far south as Antarctica. Its path transverses East Asia and the western coast of the Americas. Very roughly, the Ring of Fire outlines the Pacific Ocean. 

Since the Ring of Fire roughly outlines the Pacific Ocean, the annual precipitation within the Ring of Fire can be estimated based on the annual average precipitation over the Pacific ocean, which is 57.5 inches per year.

Generally, parts of the Ring of Fire that are closer to the equator receive more rainfall than parts of the ring that are farther from the equator. The annual rainfall at Mt. Pinatubo in the Philippines, for example, is between 80-160 inches per year, whereas the annual average rainfall of Mt. Erebus, Antarctica is 32 inches per year. Both of these places are located on the Ring of Fire, but have vastly different annual average rainfall measurements due to their proximity to the equator.

Because the Ring of Fire spans such a large portion of the globe, rainfall varies based on the location, and it would be a long process of data collection to determine the average rainfall of the entire Ring. To do so, one would have to collect data on average rainfall for a specific set of locations along the Ring. From that data, the numbers could be averaged to determine the average rainfall of the entire Ring of Fire.