Forecasting Guides

Learn how to read a weather forecast, including temperatures, precipitation probability, wind speed and direction, hourly forecasts, weather icons, UV index, and other common forecast information.

Weather models are at the heart of modern forecasting. Learn how observations become computer simulations, how models predict future conditions, and how meteorologists interpret the results.

How far ahead can weather actually be predicted? Learn how reliable 3-day, 7-day, 10-day, and longer-range forecasts are and why uncertainty increases with time.

How accurate are weather forecasts? Learn how forecast accuracy changes over time and why temperature, precipitation, storms, and other conditions can be difficult to predict.

Why did tomorrow’s forecast suddenly change? Learn why weather forecasts are updated, how new observations affect predictions, and why changing forecasts are a normal part of meteorology.

Meteorologists predict the weather by combining current atmospheric observations with computer models that forecast how temperature, pressure, wind, and precipitation will change.