process of making predictions of the future based on past and present data and most commonly by analysis of trends
Forecasting is studying and saying what is likely to happen in the future. It is similar to predicting, but usually forecasting is done with scientific methods. Forecasting can be done for many different things, like weather forecasting (predicting the weather) or economy forecasting. Science cannot know the future for sure, so forecasters try to identify the most probable events, and sometimes they are wrong.
The English Wiktionary has a dictionary definition (meanings of a word) for: forecast