The international project, which began in earnest in 2004, has moored 22 buoys so far, with plans to put down all 46 by 2012, said Michael McPhaden of the US National Oceanic and Atmospheric Administration (NOAA).
McPhaden, who is based at the NOAA's Pacific Marine Environmental Laboratory in Seattle, said the data would provide a major boost to farmers who rely on monsoon rains.
"If you know it's going to be a year of heavy rain or deficient rain, there are different seeds you can plant, different timings and types of fertilizer," he told AFP. "There are all types of strategies you can implement."
The project involves Australia, China, France, India, Indonesia, Japan and the United States, along with a coalition of eight African nations.
About a third of the world population depends in some way on the Indian Ocean's monsoon rains, which feed agriculture in Asia, Africa and Australia.
The monsoons also routinely wreak havoc, last year killing more than 800 people and displacing two million others in India alone.
Besides helping the region's farmers better predict monsoons, McPhaden said the United States had an interest as the Indian Ocean affected extreme weather in the Pacific and Atlantic oceans.
He said the Indian Ocean project modeled an effort from 1985 to 1994 that lay buoys across the Pacific Ocean, helping scientists monitor the El Nino warming effect and the related La Nina cooling phenomenon.