Factors affecting temperature
AdvancedTemperature depends on three main factors: latitude (hotter near the equator), altitude (about 6°C cooler per 1000 m) and distance from the sea plus ocean currents (the sea moderates temperatures).
- Latitude: hotter near the equator
- Altitude: about 6°C cooler per 1000 m
- Sea and currents narrow the range near coasts
§Text Passage
1Why is it snowing in Hokkaido while people in Hong Kong wear T-shirts on the very same day? This lesson unpacks the five major factors affecting temperature: latitude, altitude, distance from the sea, ocean currents and cloud cover. You will learn to explain global patterns, such as why the equator is hot and the poles are cold.
2The principle goes back to the sun. Sunlight strikes the equator head-on, so its energy is concentrated and it is hot; at high latitudes the same energy is spread thinly, so it is cold. Air on high mountains is thin and holds little heat, so summits are cooler than lowlands. The sea warms and cools slowly, keeping coasts mild in winter and cool in summer.
3Examples are everywhere: Quito, the capital of Ecuador, sits almost on the equator yet stays cool all year at nearly 3,000 m above sea level. Hong Kong averages about 16°C in January — warmer than inland cities at the same latitude because the sea moderates it. Check the outside air temperature on your next flight and you will see altitude at work.
1Summary 重點摘要
Temperature depends on three main factors: latitude (hotter near the equator), altitude (about 6°C cooler per 1000 m) and distance from the sea plus ocean currents (the sea moderates temperatures).
2Vocabulary cards Vocabulary
How far from the equator; low latitude near the equator, high latitude near the poles.
Vertical height above sea level; the higher, the colder.
Temperature falls about 6°C for every 1000 m of height gained.
Large flows of seawater; warm currents raise temperature, cold currents lower it.
The sea moderates temperature, narrowing the yearly range.
The 0° latitude line where the sun shines directly all year — the hottest zone.
Energy from the sun reaching the ground; direct rays concentrate heat, slanted rays spread it.
The gap between the hottest and coldest monthly means; small near the sea, large inland.
3Step by step Steps
- Latitude sets the baselineLatitude fixes a place's basic temperature: at low latitudes the sun strikes almost overhead, energy concentrates, and the equator is hot all year; at high latitudes the rays slant and spread over a wider area, so the poles stay freezing. Yet latitude is not the only factor: Quito in South America sits near the equator but stays spring-like all year, because it stands on a plateau nearly 3000 m high — the altitude cancels out the latitudinal heat.
- Higher means colderThe higher the ground, the thinner the air and the weaker its ability to absorb and hold heat, so temperature falls with height: on average about 6°C per 1000 m of ascent, a rule called the environmental lapse rate. Hence high summits stay cold and keep their snow. Watch the outside air temperature on a flight and you will see how much colder the upper air is than the ground — altitude at work before your eyes.
- The sea as natural air-conditioningThe sea warms and cools more slowly than land, acting like a natural air-conditioner: coastal places have neither very hot summers nor very cold winters, so their annual range is narrow, while deep inland places lose this moderation and swing widely between seasons. Hong Kong averages about 16°C in January — warmer than inland cities at the same latitude — thanks to the sea. Warm currents also warm and moisten the coasts they pass, while cold currents leave them cool and dry.
- Cloud cover counts tooCloud cover shapes the difference between day and night. On a cloudy night the cloud layer acts like a quilt, trapping the heat radiating from the ground so the temperature does not fall far; on a cloudless night the ground loses heat rapidly, the early morning turns distinctly chilly, and frost forms on just such nights. So when comparing temperatures, besides latitude, altitude and the position of land and sea, do not overlook cloud cover.
- Currents add and subtractOcean currents are conveyor belts on the sea, rewriting coastal temperatures directly: warm currents carry tropical heat towards high latitudes — the North Atlantic Drift keeps London's winter far milder than inland places at the same latitude; cold currents carry cold water towards low latitudes — the Peru Current keeps Lima on the coast cool and dry. When analysing coastal temperatures, always check first whether a warm or a cold current flows past, then judge its warming or cooling effect.
- Compare factors in pairsWhen analysing the temperature difference between two places, compare factor by factor. At the same latitude, compare altitude first: both near the equator, Singapore sits at about 27°C while Quito is only about 13°C, entirely because Quito stands nearly 3000 m higher. At the same height, compare land-and-sea position and currents: coasts have a narrow range, inland a wide one, warm currents warm and cold currents cool. Give every factor both a cause and an effect — 'high altitude means thin air, so temperatures are low' — for a complete answer.
4Diagrams Diagrams
5Worked example Example
Example: place A at the foot of the mountain (200 m) is 24°C; place B on the summit is at 3200 m. Roughly how cold is B?
- Height difference: 3200 − 200 = 3000 m
- Cooling: 3000 ÷ 1000 × 6°C = 18°C
- Temperature at B: 24 − 18 = 6°C
- Recheck: higher is colder, so the answer must be below the foot's 24°C
- Answer: About 6°C. The height difference is 3200 − 200 = 3000 m; at the environmental lapse rate of about 6°C per 1000 m the drop is 18°C, so 24 − 18 = 6°C. Check the direction: higher means colder, so the answer must sit below the foot's 24°C for the working to be sane.
6Common mistakes Mistakes
7Quick check Quick check
Q1How does temperature change per 1000 m of ascent?
Q2Why is the equator hot all year?
Q3Which has the narrower yearly temperature range: coastal or inland cities?
Q4How do warm and cold currents affect coastal temperatures? Give one example of each.
Q5Singapore and Quito both sit near the equator — why are their temperatures so different?
8Recap Recap
- Latitude: hotter near the equator
- Altitude: about 6°C cooler per 1000 m
- Sea and currents narrow the range near coasts
- Currents matter: warm ones raise, cold ones lower coastal temperatures
- Quito is near the equator yet cool — altitude near 3000 m explains it