Weather forecasters try to predict what the future weather will be. Hundreds of thousands of pieces of data are collected every day from weather stations, radiosondes, satellites, and observers. To process this amount of information requires ever more powerful computers to perform the millions of calculations per second needed to model and predict the world's ever changing weather. The mathematics of weather forecasting are very complex.

Meteorological scientists use computers to create models of the atmosphere. A typical weather forecasting model divides the globe into 90 km (56 mile) grid squares and takes readings at 19 levels. The 1,187,500 items of data obtained are processed by a computer in less than 10 minutes.

But even the most powerful computer cannot predict the weather more than about five days in advance.