Definition
The toll-free telephone number used in the United States to reach Flight Service for preflight weather briefings, flight plan filing, and other flight planning services provided by Flight Service Stations (FSS).
Plain English
A free phone number pilots call to talk to a Flight Service specialist before a flight to get weather information and file a flight plan.
Context Anchor
Seen in preflight planning discussions and in references to Flight Service Station services.
Derivation
The 'WX' is the standard aviation and meteorology shorthand for 'weather.' The number spells out 'weather brief' on a phone keypad to make it easy to remember.
Why Pilots Care
Gives pilots accurate, up-to-date weather details required for safe go/no-go decisions and route planning.
Intuition Check
Do not read 1-800-WX BRIEF as a radio frequency or call sign. It is a telephone number; “WX” means weather, and “BRIEF” points to a pilot weather briefing.
Example Sentence 1
Before the cross-country, she called 1-800-WX BRIEF to get a standard weather briefing and file her VFR flight plan.
Example Sentence 2
Even on good-weather days, many pilots still dial 1-800-WX BRIEF to confirm conditions along their planned route.