Definition
A squall is a sudden, sharp increase in wind speed of at least 16 knots, with the sustained speed reaching 22 knots or more, lasting for at least one minute. In a METAR, SQ is the contraction used to report squalls in the present weather group.
Plain English
A short, strong burst of wind that comes on quickly, gets noticeably stronger than the surrounding wind, and lasts at least a minute before easing off.
Context Anchor
Seen in METAR present-weather codes when an airport weather report is describing sudden strong wind changes.
Derivation
From an old Scandinavian word meaning a sudden gust or roar of wind. The original sense — a brief, violent burst of wind — is exactly how the term is still used in aviation weather today.
Why Pilots Care
Squalls produce rapid wind shifts that can affect aircraft control during takeoff, landing, and low-level flight.
Grounding Statement
Picture calm or moderate wind suddenly hitting the aircraft much harder and continuing for at least a minute.
Intuition Check
Do not read SQ as just “stormy weather” or “heavy rain.” In a METAR, SQ specifically points to a sudden strong wind increase.
Example Sentence 1
The METAR included SQ in the present weather group, warning the pilot of squalls moving through the field ahead of an approaching cold front.
Example Sentence 2
During the approach briefing the pilot noted SQ in the weather and prepared for possible gusts.