Weather forecasters are a much maligned lot. Nobody says that they are ever right. When they are right, nobody notices. When they are wrong, everybody does. Yet the profession has still survived. And people do check the weather forecasts.
Mumbai residents though do not need any weather forecaster. They can safely say, "It will rain the moment I step out on to the road". (during the months of June to August).
Here is a picture of a weather forecasting stone in England (found this via a forwarded mail)