Fog usually means the air near the ground is very moist and has cooled enough that tiny water droplets form and hang in the air like a low cloud.

The quick science

  • Fog is basically a cloud sitting on the ground, made of tiny water droplets that scatter light and block visibility.
  • It forms when:
    • The air is almost “full” of water vapor (near 100% humidity).
* The temperature drops to the dew point, so that vapor condenses into droplets.

Common triggers:

  • Clear, calm nights where the ground cools fast → the air just above cools too → classic morning fog.
  • Mild, moist air moving over colder ground or water → the air is chilled and fog forms (very common near coasts and in valleys).
  • In winter, snow on the ground can cool and moisten the air as it melts, helping fog form.

Why it might feel “extra foggy lately”

On days or weeks when it feels unusually foggy, there’s often a repeating pattern:

  • Long nights and weak sun (mid‑autumn to mid‑winter) so the ground stays cold and fog lasts longer.
  • Light winds: just enough to mix air a bit, but not enough to blow the fog away.
  • High pressure weather: clear skies, cool nights, trapped moist air near the surface.
  • Local geography: valleys, low spots, and areas near lakes, rivers, or the sea collect cold, moist air and get fog more often.

Why it suddenly “burns off”

People say fog “burns off,” but nothing is actually burning.

What really happens:

  1. Sunlight warms the ground.
  2. The air just above warms and can hold more moisture.
  3. The droplets evaporate back into invisible water vapor, starting at the thinner edges and working inward.

Safety check

If it’s very foggy where you are:

  • Slow down if you’re driving or biking, and use low‑beam lights, not high beams (they reflect more off fog droplets).
  • Watch for pedestrians, cyclists, and animals; distances are harder to judge.

So, “why’s it so foggy?” Most likely: cool air, very moist air, light wind, and your local landscape all lining up to turn invisible water vapor into a blanket of tiny droplets right where you live.

Information gathered from public forums or data available on the internet and portrayed here.