🌍 Weather vs. Climate The big picture
Weather is what the atmosphere is doing right now: the rain falling, the wind blowing, tomorrow's high temperature. Climate is the pattern of weather in a place over a long time, usually averaged over at least 30 years. As the saying goes, climate is what you expect, and weather is what you get.
Earth's climates are shaped by the Sun's uneven heating, the tilt of the planet, oceans and their currents, mountains, the layers of the atmosphere and the gases in them. This site tours all of it: the major climate types, the atmosphere and clouds, storms and blizzards, ocean-driven cycles like El Niño and La Niña, Kelvin waves and King Tides, droughts and floods, and then climate change: the science, the pros and cons, and what the world is doing about it. For live local forecasts see Planet Weather, and for hurricanes the Cyclone Center.
What the air is made of
Dry air by volume. Carbon dioxide is only about 0.04% of the air, yet it has an outsized effect on climate. Water vapour varies from near 0 to about 4%.
🗺️ Climates of the World
The most widely used system, the Köppen-Geiger classification, sorts the world's climates into five main groups by temperature and rainfall: A tropical, B dry, C temperate, D continental and E polar (plus highland areas). Each is split into types, shown below with a typical place and its numbers.
Compare climates in cities
Typical long-term averages, rounded. January and July are winter and summer in opposite hemispheres. Real values vary by source and period.
Why climates differ
📡 Explore the Map Climate regions, weather hot spots and live satellite layers
Pins show example climates and the places where the phenomena on this page happen. Use the layer button (top right of the map) to add NASA satellite layers: true-colour clouds, sea-surface temperature and surface air temperature, each from about two days ago. Tap a pin for a summary and use the buttons below to show or hide each kind.
Satellite layers: NASA GIBS (Terra/MODIS, GHRSST MUR, AIRS). Dates are two days back, to be sure the data have been processed. Imagery: Esri, Maxar, Earthstar Geographics.
🛰️ Layers of the Atmosphere From the ground to the edge of space
Earth's air is a thin shell: half of its mass is below about 5.5 km and 99% is below about 30 km, which is smaller than the distance of a short drive. It is divided into five layers by how temperature changes with height.
Temperature by height
Standard atmosphere (1976), approximate. Heights in kilometres on the vertical axis.
The greenhouse effect
The ozone layer
☁️ Clouds The ten basic types and what they tell you
A cloud forms when moist air rises or cools until water vapour condenses onto tiny particles, making droplets or ice crystals. Clouds are named by height (cirro- is high, alto- is middle) and shape (cumulus is heaped, stratus is layered, nimbus means rain). A cumulus cloud can weigh as much as 100 elephants or more, yet floats because its droplets are so small.
Unusual clouds
⛈️ Storms & Weather Conditions Blizzards, snowstorms, thunderstorms and more
Weather happens in the troposphere. Energy from the Sun, moisture and rising air combine with fronts, jet streams and local terrain to produce everything from fog to blizzards to tornadoes.
Blizzard or snowstorm?
Famous storms
🌊 El Niño, La Niña & Other Climate Drivers The cycles that change weather worldwide
Some of the most important influences on world weather are slow swings in the ocean and atmosphere. The best known is the El Niño-Southern Oscillation (ENSO), a natural cycle in the tropical Pacific that repeats every two to seven years and rearranges rain, drought and storms across the planet.
El Niño ("the boy")
La Niña ("the girl")
What El Niño and La Niña do around the world
These are tendencies, not guarantees: every event is different and other cycles overlap. Check NOAA's ENSO advisory for the current phase.
Kelvin waves & friends
Waves in the ocean and atmosphere carry energy over thousands of kilometres. They are how a nudge in one part of the tropical Pacific becomes a climate event on the other side of the world.
Other cycles and patterns
💧 Drought, Floods & King Tides Too little water, too much water, and the Moon
Climate is felt most through water. Too little brings drought, famine and wildfire; too much brings floods; and the oceans themselves rise and fall with the Moon, with storms and with long-term warming.
Notable events
🔥 Climate Change The science, the benefits and the costs
Earth's climate has always changed, from ice ages to warm periods, because of the Sun, volcanoes and orbit. What is different now is the speed and the cause: since the 1800s people have added huge amounts of heat-trapping gases, mostly carbon dioxide from burning coal, oil and gas, plus methane from farming, landfills and fossil fuels. Scientific assessments (the IPCC reports) find it is unequivocal that human activity has warmed the atmosphere, ocean and land.
Global temperature, 1880 to today
Approximate annual global temperature change compared with the 1951 to 1980 average, rounded from NASA and NOAA records. Each year is a bit different, but the trend is clear.
Where emissions come from
By sector, roughly, from the IPCC's 2019 assessment.
By gas
Carbon dioxide from fossil fuels and industry is the biggest share; methane is the second most important.
Evidence
Pros and cons of a warming climate
Warming does bring some local gains, which are worth understanding. But the research is consistent that, overall, the harms grow much faster than the benefits as the planet warms.
Impacts by region
🌱 What the World Is Doing Treaties, technology and adaptation
Responses fall into mitigation (cutting emissions and pulling carbon out of the air) and adaptation (preparing for the changes already underway). Progress is real but, according to the UN, current national plans still fall short of the Paris goals.
Solutions in use
Biggest emitters (CO₂ from fossil fuels)
Approximate shares of global fossil CO₂ emissions in 2023. Per person, emissions are much higher in the US, Canada, Australia and the Gulf states than in India or most of Africa. Historically, the US and Europe have emitted the most in total.