Weather forecasting is serious business for India, which has seen successive crops fail due to poor rainfall. Unlike occasional scant rainfall, India's crop need the monsoons - it's the lifeblood for farmers in the country of 1.3 billion people. Which is why India's getting rid of a 1920'a statistical method introduced under British colonial rule, instead buying a $60 million new supercomputer to improve how accurately we predict rain.

In 2015, the IMD accurately forecast a second straight drought year, in contrast to predictions of bountiful rains by Skymet, India's only private forecaster. But the weather office failed to foresee the worst drought in nearly four decades in 2009 and, as this year's monsoon starts, farmers hope its forecast of above-average rains will be right.

Because of India's size, one national forecast is of little help to farmers spread across diverse climatic zones.