What is indicated by the term "LTG FREQ" in weather reporting?

The term "LTG FREQ" in weather reporting specifically indicates frequent lightning activity. When encountered in a METAR report, it suggests that lightning strikes are occurring at regular intervals and are a significant concern for safety and navigation. Frequent lightning can pose hazards to aircraft and can be an important factor for pilots to consider during flight planning and in-flight operations.

In contrast to the other options, "infrequent lightning," "only distant lightning is reported," and "no lightning activity" do not accurately represent what "LTG FREQ" communicates. Each of these phrases indicates a different level or type of lightning, but in the case of "LTG FREQ," it clearly denotes an active and recurring occurrence of lightning.