Definition
In NOTAM and aviation weather contractions, FRZN indicates that a surface, body of water, or precipitation has solidified due to temperatures at or below 0°C (32°F). It is most often used to describe runway, taxiway, or ramp conditions, or frozen precipitation affecting an airport.
Plain English
A short way of saying something is frozen — usually a runway surface or precipitation that has turned to ice.
Context Anchor
Seen in NOTAMs and airport condition information, especially when describing runway, taxiway, ramp, or surface conditions.
Derivation
FRZN is a shortened written form of frozen. Aviation notices often shorten common words so important information fits into a compact message.
Why Pilots Care
Frozen surfaces directly affect braking action, directional control, and takeoff/landing performance. Spotting FRZN in a NOTAM is a cue to check runway condition codes and recalculate stopping distances before committing to the approach.
Intuition Check
Do not read FRZN as just meaning “very cold.” In aviation condition reports, it usually means moisture has actually turned into ice or is frozen onto a surface.
Example Sentence 1
The NOTAM read "RWY 27 FRZN PTCHY," warning pilots of patchy frozen areas along the runway.
Example Sentence 2
NOTAMs warned that several taxiways remained FRZN after the storm.