In a METAR, what does the presence of "SQ" signify?

In a METAR report, the presence of "SQ" signifies "Showers of rain." This shorthand indicates that rain is currently falling in the form of showers at the reporting station. In aviation weather reporting, descriptors like "SQ" help meteorologists quickly communicate current weather conditions that could impact flight operations.

The use of such abbreviations is standardized, allowing pilots and aviation personnel to rapidly assess weather conditions. Showers can be significant as they might affect visibility and runway conditions, making this abbreviation especially important for flight safety.

The other options represent terms that, while relevant in meteorology, do not correspond to the standard abbreviations used in METAR. For instance, "Severe squall" might be monitored in weather conditions but is not indicated simply by "SQ." Snow quality or sky quality are also important concepts but are described using different terminology, ensuring that aviators receive uniform information crucial for flying conditions.