In order to prepare a weather forecast for one day, it takes roughly 10 billion mathematical operations. These are carried out by super computers that nearly have the ability to process 2.8 quadrillion calculations a second and are gathering thousands of observations every day including air pressure, water levels, temperature, humidity and wind speed among others. These weather forecasting computers which are big in size, the size of a school bus, are vital for weather and climate forecasting in US.