Decoding Guide

Average Relative Humidity Chart


This chart depicts the average relative humidity between the surface and 500mb (18,000ft). An average relative humidity of 50% or greater is quite frequently associated with areas of clouds and possibly precipitation.


0000 and 1200 UTC

Data Sources:

Surface and upper air observations, computer models


Individual observations are depicted in white. At each station, the relative humidity value is plotted above a symbol. See the table below for an interpretation of the symbols.

Symbol interpretation:

Lifted Index Relative Humidity less than 50%
Lifted Index Relative Humidity greater than or equal to 50%
Lifted Index All significant observations missing
Lifted Index Some mandatory observations missing
Lifted Index Some mandatory and significant observations missing