What is fog?

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Key information

We see fog mainly in the autumn and winter. It's cold and damp and makes it difficult to see.

In this article you can find out:

  • How fog is formed
  • Different types of fog and how we measure it
  • How fog is used in different places around the world

This resource is suitable for Weather topics for P2, P3, P4, P5, P6 and P7 (First and Second Level Curriculum for Excellence).

Watch this video to learn about fog.

How does fog form?

  1. Fog usually happens after it's rained and there's lots of in the air.

  2. When the ground cools down, so does the air near it.

  3. When the air cools down it can't hold so much water vapour.

  4. So the water vapour condenses into cloud droplets - which we see as fog.

Foggy days and fogbows

Foggy breath

When you breath out on a cold day and see your breath, you're making your own cloud of fog!

1 of 6

  • fog– A cloud that has formed near the ground.
  • dense fog – When you can’t see further than 50 metres.
  • thick fog – When you can’t see further than 180 metres.
  • mist– When the fog is thin enough that you can see one kilometre away.
  • fog bow – A fog bow looks like a rainbow, but is pale and hazy instead of colourful.

Try this short multiple choice quiz to test your knowledge of fog

Create and give a presentation about fog.

Hopefully you've learned a lot about fog and how it can be used in different ways across the world. Can you explain what you've learned in a presentation?

Before you give your presentation, you might want to think about some of these tips:

  • Remember to prepare any points, slides and props you might have.
  • Think about who your audience is.
  • You can use graphs, charts or quotes to support your ideas.
  • Make eye contact with the audience and speak clearly.

If you need more help on giving a presentation, here is a video to help: How to give a presentation.