Definition
A cockpit system that receives weather information from a ground-based or satellite-based service and displays it on an aircraft's avionics, typically as graphical overlays on a moving map. Common products include radar imagery (NEXRAD), METARs, TAFs, AIRMETs, SIGMETs, winds aloft, and lightning. Most general aviation data link weather is delivered either by satellite subscription services (such as SiriusXM Aviation Weather) or by the FAA's free Flight Information Service-Broadcast (FIS-B) over the ADS-B network.
Plain English
A way for the airplane to receive up-to-date weather pictures and reports in flight, so the pilot can see things like storms, cloud cover, and reported conditions on a cockpit display instead of only hearing them on the radio.
Context Anchor
Seen on cockpit displays and safety-system diagrams that show how weather information can be sent to the aircraft during flight.
Derivation
WX is the long-standing telegraph and aviation shorthand for weather. A data link is simply a one-way or two-way electronic connection that carries digital information. Together, the term means a digital link that delivers weather to the cockpit.
Why Pilots Care
Allows pilots to spot and avoid dangerous weather ahead, supporting safer route decisions.
Analogy
It is like checking a weather map on your phone while traveling: it gives you useful information over a wide area, but it may not show exactly what is happening at your location this second.
Intuition Check
Do not assume WX Data Link is live weather radar. It receives weather information from outside sources, and that information may be several minutes old by the time it appears on the display.
Example Sentence 1
Before crossing the ridge, she checked the WX data link display and saw a line of returns building to the west.
Example Sentence 2
While flying in clouds, she used the WX Data Link to receive updated precipitation reports.