i am has got two monsoon forecasts right in the past decade, once in 20 11 and another in 20 17. But predictions qan quickly go awry when you're talking about chaotic systems where a mish mash of variables can deeply affect future outcomes. No man made computer model can account for all these variations, and so the predictions will always have a margin of error. However, this margin dissipates overtime. For instance, a seven day forecast can accurately dict the weather about 80 % of the time,. A five day forecast can accurate predict the weather approximately 90% of the time.