Which weather condition is indicated by "SN"?

"SN" is the abbreviation used in METAR reports to denote "snow." This code indicates that snow is falling or is expected to fall in the vicinity of the reporting station. When analyzing METAR codes, it's important to understand that specific abbreviations are designated for various weather phenomena, and "SN" is universally recognized within aviation and meteorological communities as representing snowfall.

In contrast, other options do not accurately reflect the meaning of "SN." "Shower" and "storm" have their respective abbreviations in METAR codes, such as "SH" for showers and "TS" for thunderstorms. "Sunny" is not represented by a specific code in METAR reporting but would typically not be included as a weather condition in the format of these reports. This specificity in coding is essential for clear and effective communication of weather conditions in aviation and meteorology.