A weather forecast is a prediction of future atmospheric conditions. It may cover the next few hours or extend out to a week or more. Forecasts are based on observations, numerical models, and the experience of meteorologists.

Short-range forecasts focus on the details of precipitation, temperature, and wind. Medium-range forecasts emphasize the overall pattern and the probability of different outcomes. Uncertainty increases with time, which is why ensemble methods and probabilistic language are increasingly used.

Forecasts are communicated through apps, broadcasts, websites, and specialized products for aviation, marine, and emergency management users. Verification against later observations continually improves the system. Even with advanced models, human interpretation remains valuable for complex situations.

The quality of forecasts has improved steadily over recent decades, yet the atmosphere’s chaotic nature sets fundamental limits.