Measuring system of adverse weather phenomena

A measuring system of adverse weather phenomena by unification of threshold scales and their units has been defined. All threshold scales of adverse weather phenomena have been reduced to three different types: standard frequency distribution, decile method and Beaufort scale. Their units are: standard deviation, decile of frequency and unit of the Beaufort scale. Four steps for each threshold scale are defined: normal, above normal, much above normal and extraordinary above normal or normal, below normal, much below normal and extraordinary below normal. The examples by observations of Meteorological Observatory in Belgrade are presented.