Mesosphere

The mesosphere is located between 50 and about 80 kilometres altitude, above the stratosphere (which is located above the troposphere, which is in contact with the ground).

It is separated from the stratosphere by the stratopause and from the upper layer (the thermosphere) by the mesopause.

At a minimum temperature of about -100 °C, it is the coldest layer of the atmosphere. Water vapour can freeze there, forming particular clouds such as iridescent noctilucent clouds.