Temperature and Weather

Core Idea

Temperature tells us how hot or cold the air is. The sun warms the Earth and the air around it. When the sun is strong, temperatures are higher and we feel warm. When the sun is weak or absent (nighttime), temperatures drop and we feel cool or cold. Temperature is one of the most important parts of weather because it affects what we wear, what falls from the sky (rain vs. snow), and how comfortable we feel.

How It's Best Learned

Use a large classroom thermometer and read it together each morning. Compare morning vs. afternoon temperatures. Discuss what clothing is appropriate for different temperatures. Connect temperature to personal experience: "When it is 30 degrees Celsius, how do you feel? When it is 0 degrees?"

Common Misconceptions

• The sun is closer to Earth on hot days and farther away on cold days. Temperature changes are mostly caused by the angle of sunlight, not distance.
• Temperature is the same everywhere at the same time. Shady spots, sunny spots, and different cities all have different temperatures.
• Cold means the sun is not working. The sun is always producing energy; cold days happen when less of that energy reaches the surface.

Explainer

When you walk outside, one of the first things you notice is whether the air feels hot or cold. That feeling has a name: temperature. Temperature is a measurement of how warm or cool the air is, and it is one of the most important parts of weather.

The sun is what makes the Earth warm. Sunlight travels from the sun to the Earth, and when it hits the ground, the ground absorbs that energy and heats up. The warm ground then heats the air sitting on top of it. That is why the ground on a sunny day feels hot under your feet -- it has been soaking up sunlight. It is also why the afternoon is usually warmer than the morning: by afternoon, the sun has been warming the ground for hours.

At night, the sun is not shining on your side of the Earth, so the ground slowly releases its heat and cools down. The air cools down too. That is why early morning, just before the sun comes up, is usually the coldest part of the day -- the ground has been cooling all night long with no sun to warm it.

Temperature matters because it affects so many things. It determines what you wear -- shorts and a T-shirt when it is hot, or a heavy coat and gloves when it is cold. It determines whether water falling from clouds will be rain (when the air is warm enough for liquid water) or snow (when the air is cold enough for water to freeze). And it affects how plants grow, when animals are active, and how comfortable people feel. Learning to pay attention to temperature is one of the first steps in understanding weather.