From a few weeks to a few years in advance, climate forecasts predict weather averages and other climatic features. Forecasters are increasingly relying on detailed models of the Earth's climate system to generate such predictions. Climate models are also used by researchers to project forced changes many decades into the future under various human-induced scenarios.
Weather forecasting is the use of science and technology to forecast atmospheric conditions for a specific location and time. For millennia, people have sought to predict the weather informally and systematically since the nineteenth century. Weather predictions are created by gathering quantitative data on the current state of the atmosphere, land, and ocean, and then applying meteorology to project how the atmosphere will change at a certain location. Weather forecasting is currently based on computer-based models that take many atmospheric aspects into account, rather than being estimated manually based on changes in barometric pressure, present weather conditions, and sky condition or cloud cover. Pattern recognition skills, teleconnections, knowledge of model performance, and understanding of model biases are still required for selecting the best potential forecast model on which to base the forecast.