What this lesson teaches
I can tell weather from climate, name the main climate types, and describe the hazards each brings.
Syllabus K226, Topic 3.1, Key Question 1. What is weather and climate?
Make a guess
It has not rained in Singapore for two weeks in February. What does this tell you about Singapore's climate?
- The climate of Singapore has changed for good.
- Singapore's climate is drier than its rainfall averages suggest.
- February must be the driest month of Singapore's year.
- Very little. Climate is a pattern over many years.
Show the answer
Very little. Climate is a pattern over many years.
Two dry weeks are weather, not climate. Climate averages usually cover 30 years, and single months can be wetter or drier than normal.
Weather is what the air is like now; climate is the pattern over many years.
Weather is the state of the air at one place and time. It includes temperature, cloud, rain, wind speed and wind direction. An afternoon thunderstorm is weather. The pattern over many years is climate.
A climate average usually covers 30 years, such as 1991 to 2020. Single months can still be wetter or drier. Before reading a climate graph, check the place, the years and the units.
Tropical equatorial climates are warm all year, with heavy rain and a small temperature range. Tropical monsoon climates are also warm, but have clearer wet and dry seasons. Cool temperate climates are cooler, with bigger changes between seasons, and their rainfall varies from place to place. Use the whole pattern of temperature and rain to name a climate type.
Climatic hazards harm people and nature. Heat waves bring long spells of heat. Droughts cut water supplies. Floods damage homes, crops and habitats. Tropical cyclones bring strong winds, heavy rain and storm surges. Hot, dry weather helps wildfires spread. A hazard becomes a disaster when people are exposed and cannot cope.
- Weather
- Conditions at one place and time.
- Climate
- The average pattern over about 30 years.
- Temperature range
- Highest monthly mean minus lowest monthly mean.
Step by step
Read the axes
Check the place, years and units. Rain and temperature use different axes.
Describe the year
Give the main patterns, with months and values.
Work out the range
Subtract the lowest monthly mean temperature from the highest.
Worked example: A precise graph description
Changi is warm all year: monthly means range from 26.8 to 28.6 degrees C, a range of 1.8 degrees C. Rain falls every month. December averages 331.9 mm, while February averages 105.1 mm. This is the normal pattern, not a forecast for one December day.
Watch out for this
A dry February means Singapore has a dry climate.
February is only drier than other months. Use the whole year and the long-term record to describe climate.
Check your understanding
Which statement is evidence about climate?
- Rainfall averaged over 1991-2020 peaks in December.
- The wind changed direction at 2 pm today and has stayed northeasterly.
- Tomorrow afternoon may bring thunderstorms across the whole island.
Show the answer
Rainfall averaged over 1991-2020 peaks in December.
Yes. A long-term average describes climate.
Check your understanding
A place gets at least 60 mm of rain every month and temperatures of 26-28 degrees Celsius all year. Which climate is it?
- Tropical equatorial.
- Tropical monsoon climate.
- Cool temperate climate.
Show the answer
Tropical equatorial.
Warm all year with rain in every month.