Final answer:
The word that best fits in the blank is incessant. Incessant means continuing without interruption or non-stop. It describes the rain that kept the person wet throughout the camping trip.
Step-by-step explanation:
The word that best fits in the blank is incessant. Incessant means continuing without interruption or non-stop. In this context, it means the rain continued and did not stop during the entire camping trip, causing you to get wet. An example sentence using incessant in this context would be: "The incessant rain kept us wet during our entire camping trip."