Estimation of the height of the cloud base

Diurnal, seasonal, locational variations

Diurnal variations

The normal day and night variation of temperature affects the height of the cloud base of some clouds, mainly the low clouds.  The following remarks may be helpful:

  • Stratus tends to form at night, and to lift or disperse during the day.  Fog may form overnight and then lift during daylight to form stratus.

  • Stratocumulus usually has the same tendency to form at night and lift or disperse during the day.  However, this cannot be taken as a general rule, as on some occasions Stratocumulus will tend to thicken during the day, and the base becomes a little lower.

  • Cumulus often forms during the day and disperses late in the day or evening.  Cloud base usually gradually becomes higher during the day. Cumulus at night or early morning is not so common, except in tropical areas, or when associated with cold fronts or other weather systems.

Season and location variations

The height of clouds will vary with season and location; the variations are dependent on temperature and the water content of air or surface.  Although generalising here, this may be useful when an Observer moves from one location to another.

For a given latitude, clouds tend to be:

  • Lower in winter and higher in summer

  • Lower over the oceans/near the coast and higher inland

  • Lower over hills and higher over plains