How can visibility in a METAR/SPECI report be identified?

Visibility in a METAR/SPECI report is identified by the presence of "SM" which stands for statute miles at the end of the visibility group. This indicates the visibility is reported in statute miles, which is the standard method for reporting visibility in aviation meteorology in the United States.

The visibility information is crucial for pilots and air traffic controllers as it provides insights into current weather conditions affecting flight operations. Statute miles are a familiar unit for most U.S. operators, making "SM" an essential part of these aviation weather reports.

The other options, while they mention terms related to visibility, do not provide the correct format for identifying visibility in these reports. "M" at the beginning of the group is not relevant to visibility and could refer to other data points in the METAR report. "M" at the end signifies meters, which is not the same as statute miles and would not typically be the correct format for U.S. reporting. "VV," which stands for vertical visibility, indicates visibility conditions in a different context and is not the standard identification for horizontal visibility in METAR reports.