Which visibility condition is less than 3 statute miles?

Visibility is a crucial aspect of aviation weather reporting, as it affects flight operations and safety. In the context of METAR reports, visibility is typically expressed in statute miles (SM).

The question asks for a visibility condition that is less than 3 statute miles. To understand why the selected answer is correct, let's evaluate the option. A visibility of 2 1/2 statute miles indicates that visibility is indeed less than 3 statute miles, making it the appropriate choice.

The other options provide visibility readings that meet or exceed the threshold of 3 statute miles. For instance, 5 statute miles, 3 1/2 statute miles, and even 1 statute mile (although less than 3, is not the highest value below that threshold compared to 2 1/2 SM). However, these values are either too high or do not fit the specific criteria of being less than 3 statute miles in the case of 5 SM and 3 1/2 SM, which are both above 3 SM, while 1 SM, although less than 3 SM, is not the only qualifying figure.

Thus, 2 1/2 SM is the only option that correctly satisfies the condition of being less than