Weather is what the air is doing today. Climate is the usual pattern of weather over many years: how warm, how wet, and when. You already know latitude and the equator. Latitude is the biggest climate control, but not the only one.
Key idea
Six things together set a place's climate: latitude, elevation (height above sea level), nearness to the ocean, ocean currents, winds, and mountains that block rain.
| Control | What it does | Example |
|---|---|---|
| Latitude | Near the equator the Sun is high all year: warm. Near the poles it is low: cold. | Singapore is hot; Oslo is cool |
| Elevation | Air gets colder as you go up, about 6.5 °C for every 1,000 m on average. | Quito, Ecuador, almost on the equator, is mild all year at 2,850 m |
| Nearness to the ocean | Water heats and cools slowly, so coasts have milder summers and winters. | Coastal San Francisco against inland Sacramento |
| Ocean currents | Warm currents warm the coasts they pass; cold currents cool them. | The North Atlantic Current keeps western Europe mild |
| Winds | Winds from the sea bring moist air; winds from inland bring dry air. | Monsoon winds bring the summer rains to India |
| Mountains | Moist air rises and rains on the windward side; the far side is dry, a rain shadow. | The Andes shelter the Atacama Desert |
Why it works
Climate is about energy and water. Latitude sets the sunshine; thin air high up holds less heat; oceans store summer heat and give it back in winter; winds and currents carry heat and moisture; mountains make air rise, cool and drop its rain.
Worked example: Going up
A town at sea level has an average temperature of 26 °C. About how warm is a mountain village 2,000 m higher nearby? Use 6.5 °C per 1,000 m.
- 2,000 m is 2 thousand meters.
- 2 × 6.5 = 13 °C cooler.
- 26 − 13 = 13 °C.
Answer: About 13 °C.
Worked example: Coast or inland?
Two cities are at the same latitude. One is on the coast, the other far inland. Which has colder winters?
- The ocean warms coasts in winter.
- Inland, nothing holds the heat.
Answer: The inland city.
Common mistake
Thinking climate depends only on latitude. Quito sits almost on the equator but averages only about 14 °C, because it is 2,850 m high. London and Calgary, Canada, are at similar latitudes, but London's winters are far milder thanks to the ocean and the North Atlantic Current. Try it in the Climate Factors lab, linked on this page.