Cloud and Rain Droplets; (There are four different sizes of droplets.)
Rain Droplets -(Diameter) 2mm
Drizzle droplets -(Diameter) 0.3mm
Giant Cloud droplets-(Diameter) 0.1mm
Cloud droplets-(Diameter) 0.02mm
Just so that you know, mm stands for Milli Meter and is one one thousandth of an inch.
(mm is part of the Metric System. I'll do a post on it pretty soon.)