Climate

Climate is the long-term pattern of weather in a particular place or region, averaged over many years. While weather describes the state of the atmosphere from day to day — temperature, rainfall, wind and cloud at a given moment — climate summarises the typical conditions and their variation across the seasons over decades. The scientific study of climate is called climatology, and it draws on meteorology, the study of weather processes in the atmosphere.

A region's climate is shaped by several factors. Latitude controls how much solar energy an area receives, producing the broad contrast between hot tropical, temperate and cold polar zones. Distance from the sea moderates temperatures, since water heats and cools more slowly than land. Altitude lowers temperature with height, and the pattern of prevailing winds and ocean currents redistributes heat and moisture across the globe. The atmosphere itself, a layered envelope of gases, governs much of this behaviour: differences in pressure drive winds, and the rotation of the Earth deflects them through the Coriolis effect, giving rise to large-scale circulation and features such as land and sea breezes.

Climate is not fixed. Over long periods it changes naturally, and in recent times human activity has altered it by increasing the concentration of greenhouse gases, leading to global warming — a rise in average global temperature with wide-ranging effects on weather patterns, ice cover and sea level. Understanding climate therefore combines the study of present-day weather processes with the analysis of how those processes shift over time.

Frequently asked questions

What is the difference between weather and climate?

Weather is the atmosphere's condition at a given moment, while climate is the average pattern of weather in a region over many years.

What factors determine a region's climate?

Latitude, distance from the sea, altitude, prevailing winds and ocean currents all influence the temperature and rainfall a place typically experiences.

What is global warming?

It is the long-term rise in Earth's average temperature, driven in recent times largely by increasing greenhouse-gas concentrations from human activity.