Weather

Weather is the day-to-day state of the atmosphere in a particular place, including temperature, wind, rain, cloud cover and humidity. It affects many parts of our lives, from what we wear to flooding, heatwaves and other extreme weather events. Understanding weather helps us prepare for hazards, protect communities, and respond to the growing impacts of climate change.

Temperature measures the average kinetic energy of air molecules, indicating the degree of hotness or coldness and determining the spontaneous direction of atmospheric heat flow.

Air pressure is the total weight of the atmospheric air column pressing down on Earth’s surface, a crucial metric that meteorologists measure using a barometer.

Humidity measures the amount of moisture or water vapor present within the air, which directly affects how warm or cold the environment feels to us.

Wind is the horizontal movement of air across Earth’s surface, driven primarily by pressure differences as air flows from high pressure towards low pressure zones.

Convection is the vertical transport of heat and moisture, where warm, less dense air rises upward, frequently fueling cloud development and storms in the process.

Cloud condensation nuclei are tiny microscopic particles, like dust, smoke, or sea salt, providing physical surfaces where water vapor condenses to form individual cloud droplets.

Precipitation is liquid or frozen water – like rain, snow, sleet, or hail – that forms in clouds and falls to Earth when it becomes too heavy.

Cyclones are low-pressure weather systems with inward-spiraling winds causing stormy weather, while anticyclones are high-pressure weather systems with outward-spiraling winds that bring calm, clear skies.

A storm is a weather system with strong winds that often brings heavy rain, snow or flooding, developing when differences in atmospheric pressure cause air to move through the atmosphere.

A jet stream is a fast-moving band of high-altitude winds, typically six to nine miles high, that plays a critical role steering global weather systems.

A monsoon is a seasonal shift in prevailing winds that creates distinct wet and dry periods, primarily affecting tropical and subtropical regions across the globe.

A heatwave is a prolonged period of unusually hot weather for a particular location. Heatwaves often develop when high-pressure weather systems remain over an area for several days or weeks, bringing sustained high temperatures. Climate change is making heatwaves more frequent and intense, increasing risks to people, infrastructure, and the environment.

A cold spell is a period of unusually cold weather for a particular location and time of year. Cold spells can disrupt travel, affect agriculture, and increase risks to health, especially for vulnerable people. As the climate warms, cold spells are expected to become less frequent in many regions, although they will still occur.

A drought is a prolonged period of below-average rainfall that can lead to water shortages, dry soils and increased wildfire risk. Droughts can affect agriculture, ecosystems, and access to water, with impacts on communities, food production and the environment.

The El Niño–Southern Oscillation (ENSO) is a natural climate pattern shifting tropical Pacific ocean temperatures and atmospheric pressure, altering global weather every 2 to 7 years.

La Niña is a natural climate pattern (part of ENSO) in which cooler-than-average sea surface temperatures in the tropical Pacific Ocean influence weather patterns around the world, affecting rainfall, temperatures, and storm activity.

El Niño is a natural climate pattern (part of ENSO) in which warmer-than-average sea surface temperatures in the tropical Pacific Ocean influence weather around the world, affecting rainfall, temperatures, and extreme weather events.

Scientists forecast the weather by combining observations from satellites, weather stations, aircraft, and radar with computer models that simulate how the atmosphere will change. By analysing this data, they can predict future weather conditions.

Weather affects air quality by influencing how pollutants are dispersed or removed from the atmosphere. Wind can carry pollutants away, rain can wash them out of the air, and hot, still conditions can allow pollution to build up near the ground.