This is one of the most commonly asked questions. The answer depends on which maps you are looking at. Most often this question refers to the radar maps commonly seen in television broadcasts, which tell about weather moving through your area.

There are different types of weather maps.  What you are most likely talking about is the color radar maps seen on TV.

The different colors represent the intensity and precipitation.  The colors represent decibels of Reflectivity (Dbz), which is the amount of power reflected back to the radar receiver. 

if you look at the maps, you will see a Dbz scale right next to the color scale.  The two are related.  As the strength of the signal reflected back to the receiver increases, the Dbz number increases.

The scale relates to the intensity of rainfall as well.  The higher the Dbz, the stronger the rainfall.  Hail, for example is a good reflector of energy and will return very high Dbz values.

In addition, these maps show movement and locations of weather phenomena.  These radars can show us many things, like the hook echoes which are indicative of a tornadic thunderstorm.

Also, it is not well known that radars have two modes.  One is the precise clear air mode and the other is a precipitation mode.  

GENERALLY SPEAKING HERE ARE THE MEANINGS OF COLORS:

• Green corresponds to lighter precipitation, often not hitting the ground.  Light green is often “ground clutter”, which are essentially false echoes
• Darker Green  is usually light, approaching moderate rain     
• Yellow moderate rain
• Orange heavier rain
• Red heaviest rain, flooding rains, possibly hail or damaging winds and thunderstorms
• Light pink corresponds to light freezing rain and/or sleet possibly mixed with rain or snow.
• Darker pink corresponds to heavier icy precipitation.
• Light gray corresponds to lighter snowfall
• Bright white corresponds to heavier snowfall.

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