Weather vs climate

§Text Passage

1Summary 重點摘要

Weather is the atmosphere over hours to days; climate is the long-term (usually 30-year) average. Six weather elements: temperature, rainfall, wind, humidity, cloud cover and pressure.

2Vocabulary cards Vocabulary

3Step by step Steps

1. Weather = clip, climate = averageWeather is the state of the atmosphere over a short time, like a short clip: 'hot and rainy today'. Climate is the average of many years of weather, like a long documentary: 'Hong Kong summers are hot and wet'. The two differ completely in time scale, and this is the key test. In answers, decide first whether a moment's condition or a long-term average is being described, and the two concepts will never be confused.
2. Six weather elementsTemperature, rainfall, wind, humidity, cloud cover and pressure are the six weather elements, wind covering both direction and speed. Each element has its matching instrument: a thermometer for temperature, a rain gauge for rainfall, a wind vane and anemometer for wind, a hygrometer for humidity and a barometer for pressure — never mismatch the pairs. Correct pairing of elements and instruments is the basic requirement in observation questions.
3. The Observatory watches for youThe Hong Kong Observatory issues daily weather reports and warnings — the No. 8 tropical cyclone signal, and the amber, red and black rainstorm warnings — on which the public plans travel and activities. These forecasts are not guesses: instruments at observation stations across the territory measure temperature, rainfall, wind, humidity, cloud cover and pressure without pause, and analysts work the data up, showing how closely the six elements touch daily life.
4. Don't mix them up'33°C today' describes a single day and is weather; 'records began in 1884, Hong Kong averages about 2,400 mm of rain a year, and the climate is warm and humid' quotes a multi-year average and is climate. Remember that one day's data cannot overturn a decades-long average: a few unusually cool days do not change the long-term pattern of hot Hong Kong summers. Keep the distinction clear and your answers will stand firm.
5. Wind direction names the sourceWind direction tells you where the wind comes from: an easterly blows from the east towards the west. Wind speed measures how fast the air moves, in kilometres per hour, read from a wind vane and an anemometer. Hong Kong's summer winds are mostly southerly, carrying warm moist sea air ashore, while winter winds are mostly northerly, bringing dry cool air from the inland. The seasonal reversal of wind is a major reason for Hong Kong's wet summers and dry winters.
6. Where climate normals come fromAverage thirty consecutive years of observations and you obtain a climate normal: averaging the January means of 1991–2020, for instance, gives Hong Kong's January normal of about 16°C. A span as long as thirty years is chosen because unusually warm or cold years cancel one another out, leaving the steady pattern we call climate; the World Meteorological Organization updates regional normals on exactly this basis.

4Diagrams Diagrams

5Worked example Example

6Common mistakes Mistakes

7Quick check Quick check

8Recap Recap

• Weather is short; climate is the long-term average
• Six elements: temperature, rainfall, wind, humidity, cloud, pressure
• Each element has its own instrument
• One day's weather cannot tell the climate — look at long-term averages
• The Observatory measures the six elements to issue forecasts and warnings