1.Weather forecasts are created by gathering as much information as possible about the current condition of the atmosphere (especially temperature, humidity, and wind) and applying knowledge of atmospheric processes (through meteorology) to predict how the atmosphere will change in the future.
2.computer weather models - Extremely powerful computers utilize data about what the weather is already doing and what it has behaved in the past to forecast how it will behave in the future. They do several computations to determine what is most likely to occur.
3.Meteorologists now employ complex mathematical equations to help anticipate the weather as part of a process known as numerical forecasting. Many individuals build their backyard weather stations, complete with thermometers for temperature and rain gauges for precipitation.