Precipitation of liquid water drops greater than 0.5 mm in diameter. In contrast to showers, it is steadier and normally falls from stratiform (layer) cloud.
A form of precipitation. It is any liquid deposit that falls from clouds in the atmosphere to the ground surface. Rain normally has a diameter between than 0.5 and 5.0 millimeters.
Precipitation in the form of liquid water drops that have diameters greater than 0.5 mm, or, if widely scattered, the drops may be smaller. The only other form of liquid precipitation, drizzle, is to
be distinguished from rain in that drizzle drops are generally less than 0.5 mm in diameter, are very much more numerous, and reduce visibility much more than does light rain. For observing purposes, the intensity of rainfall at any given time and place may be classified as 1) "light," the rate of fall varying between a trace and 0.25 cm (0.10 in.) per hour, the maximum rate of fall being no more than 0.025 cm (0.01 in.) in six minutes; 2) "moderate," from 0.26 to 0.76 cm (0.11 to 0.30 in.) per hour, the maximum rate of fall being no more than 0.076 cm (0.03 in.) in six minutes; 3) "heavy," over 0.76 cm (0.30 in.) per hour or more than 0.076 cm (0.03 in.) in six minutes. When rain gauge measurements are not readily available to determine the rainfall intensity, estimates may be made according to a descriptive system set forth in observing manuals.
Precipitation consisting of a mixture of rain and wet snow. It usually occurs when the temperature of the air layer near the ground is slightly above freezing. The British term for this mixture is sle
et (which has a different meaning in the United States).
A type of snow crust formed by refreezing after surface snow crystals have been melted and wetted by liquid precipitation. This type of crust is composed of individual ice particles such as firn. Rain
may also help to form film crust or ice crust.