FAQs - Weather

1. How far ahead can we predict the weather and climate these days?

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. Information can be disseminated around the world from one location to another within three hours, while recently understood phenomena such as El Niño Southern Oscillation (ENSO) (El Niño, La Niña and neutral phases) can be forecast up to a year in advance. Seasonal climate predictions can be forecast up to a month, three months or six months ahead although these climate predictions are probabilistic in nature. Such forecasts, often from more advanced centres, are made available globally to all nations.

2. Why are weather forecasts sometimes inaccurate?

Air pressure, temperature, mountain ranges, ocean currents and many other factors combine to produce an enormous quantity of interacting variables all of which can alter the weather to a greater or lesser extent. However, greater understanding of the science, plus the use of powerful computer models, continue to improve our ability to make more accurate predictions with longer lead times.

3. How can we improve weather and climate forecasts?

Observations from various instruments are crucial to understand how the atmosphere, oceans, rivers and lakes, land surface as well as the biosphere influence our weather, climate and hydrology. Powerful computers in global centres process these quality-controlled data from instruments and Earth-observing satellites to be used in numerical models based on physical laws to produce weather, climate and water-related forecasts, predictions, and information products and services for use in daily lives, long-term decision-making and research. Without these valuable inputs from observations, the quality of the models is compromised. 
Another important aspect is the quality of the numerical models themselves. Due to the complexity of the processes governing weather, climate and hydrology, some approximations have to be made in the computer models. Model developer work continuously on improving the accuracy of numerical models, while also lessening the number of assumptions that have to be made. Advancing the accuracy of the models also requires collaboration with computer scientists to tap the progress being achieved in super computing. Since the first weather forecasts of the 1950s, advancements in numerical weather prediction, and more recently in climate projections, have gone hand-in-hand with progress in scientific computing capabilities.

The World Weather Research Programme (WWRP) and the World Climate Research Programme (WCRP) now focus on identifying problems with forecasting the weather and climate in a seamless fashion, i.e. crossing the artificial and historical border between weather and climate. The possible areas of improvement include:

  • enhanced observation and data analysis systems 

  • increased understanding of atmosphere dynamics and predictability
  • higher spatial and temporal resolution of remote sensing instruments
  • formulation and methodological approaches of our numerical models on all time scales
increased accessibility to global, regional and national numerical weather prediction outputs

Another aspect is the proper communication of weather forecasts and warnings, with information tailored to the needs of the user of the forecast, for example emergency managers or the general public.

Capacity building of technicians who maintain instruments and of meteorologists and climatologists on the optimal use and interpretation of prediction tools (especially in developing countries) to improve decision-making is absolutely necessary.

4. Will we ever be able to control weather in the future?

Experiments on weather modification have been, and continue to be, carried out. The most prevalent method is cloud seeding, which dates back to 1946 and is the attempt to alter the amount or type of precipitation produced by clouds. This is done by targeting clouds from aircraft or from the ground with substances such as silver iodide, dry ice and even salt. In the 1950s and 1960s, US scientists experimented in modifying tropical cyclones (Project Stormfury) but the research was inconclusive. 

Today, cloud seeding is employed in many countries in an effort to increase precipitation in drought-stricken areas, reduce the size of hailstones that form in thunderstorms, reduce fog around airports and even to provoke snow at major ski resorts. However, the impacts of operations in rainfall enhancement and hail suppression have still not been properly quantified and modification remains an area of active research.

5. Why is it that developing nations always seem to suffer most during extreme weather events?

Every year, natural disasters affect many communities around the world, leading to the loss of lives, the destruction of social and economic infrastructure and the degradation of already fragile ecosystems. Such hazards are inevitable and can threaten everyone, but they tend to hit communities in developing and least developed countries the hardest, increasing their vulnerability and setting back their economic and social goals, sometimes by decades. 

While economic losses in dollars for developing countries are lower than those for developed countries, impact (as a percentage of GDP) is often much higher. Many developing nations lie in tropical zones where extreme weather events such as tropical cyclones, droughts and flooding are more frequent than in other regions. Developing nations possess limited facilities and qualified human resources to monitor and predict these phenomena and provide warnings to all sectors of the population. Addressing this challenge is a major concern for WMO.

6. How can I become a meteorologist?

Meteorology requires knowledge of higher mathematics, physics and chemistry as well as good computer proficiency. The basic requirement for becoming a Meteorologist is a BSc degree in Meteorology or Atmospheric Sciences. Another option is to first get a BSc in Mathematics, Physical Sciences or Engineering and then follow courses in Meteorology. Teaching, research or management positions usually require higher degrees. Meteorological technicians, who may not possess an academic degree, generally undertake the responsibility of collecting and reporting observational weather data. Their qualification is normally obtained through completion of technical-level courses of a varying duration (between a few months and 1-2 years) depending on the envisaged work.


We need weather forecasts to know what to wear, to plan our day and to prepare for natural hazards that may lie ahead. However, weather forecasts provide essential information for decision-making in many other areas: