Your Window to the World's Weather

A five-day weather forecast today is generally as reliable as a three-day forecast two decades ago. Outlooks of up to a week, especially in temperate mid-latitude regions, are becoming increasingly reliable. Seasonal climate predictions can be forecast up to six months ahead, though these are probabilistic in nature.

Air pressure, temperature, mountain ranges, ocean currents, and many other factors combine to produce an enormous quantity of interacting variables. However, greater understanding of the science, plus powerful computer models, continue to improve prediction accuracy with longer lead times.

While economic losses in dollars for developing countries are lower than for developed countries, impact as a percentage of GDP is often much higher. Many developing nations lie in tropical zones where extreme weather events are more frequent, and possess limited facilities to monitor and predict these phenomena.

Weather modification experiments like cloud seeding have been conducted since 1946. Today, it's employed in many countries to increase precipitation in drought areas, reduce hail, and clear fog near airports. However, impacts remain difficult to quantify and weather modification continues to be an area of active research.