Definition
In weather radar, the measure of how strongly a target — such as raindrops, snowflakes, or hail — returns the radar's transmitted energy back to the receiving antenna. Higher reflectivity values indicate larger or more numerous precipitation particles, and are displayed on radar imagery as more intense colors (typically yellows, oranges, and reds).
Plain English
How much of the radar's signal bounces back from precipitation. Bigger or denser drops bounce back more signal, which shows up as brighter, hotter colors on the radar picture.
Context Anchor
Seen on weather radar displays and radar observation figures, where different colors or shading show areas of weaker or stronger weather returns.
Derivation
From Latin reflectere, meaning 'to bend back.' In radar, it describes how much energy is bent back toward the antenna after striking a target — useful because the term is built around the idea of returning signal, which is exactly what the radar measures.
Why Pilots Care
Higher reflectivity values indicate more intense precipitation, helping pilots avoid hail, heavy rain, and turbulence.
Analogy
Think of shining a flashlight into falling rain. Big, dense raindrops send more light back to your eyes than a light mist; radar reflectivity is the radar version of that idea.
Grounding Statement
If you shine a flashlight at different surfaces, some bounce back more light than others — radar reflectivity is the same idea, but with radar energy bouncing off raindrops.
Intuition Check
Reflectivity does not mean how shiny a cloud is. In this context, it means how much radar energy comes back from rain, hail, or snow inside the weather.
Example Sentence 1
The high reflectivity values on the radar display indicated a strong thunderstorm cell along the planned route.
Example Sentence 2
Pilots use reflectivity levels above 40 dBZ to identify areas that may contain hail.