Why does dew form?

How dew forms

Dew forms when the air cools down at night. This process is called condensation .

There is always water vapor in the air. This is called humidity . Warm air can hold a lot of water vapor, but cold air can hold less. When the temperature goes down, some of the water vapor in the air turns into water. We call this water dew .

Dew usually forms when the temperature falls to about 0–10°C , especially in the early morning.

The extra moisture becomes tiny drops of water and settles on cold surfaces, such as grass, leaves, and cars.