The Left Fork hike leading to the Subway requires a permit. While generally one needs to participate in a lottery three months ahead of time to obtain one, I was lucky enough to get my hands on one; later in the season, I was able to do the hike again in the sun.
It poured from the second we left the car. At one point, I heard a crash and turned around to find a waterfall had appeared from out of the air. But the Subway itself was absolutely magical.
While it perhaps may have been nicer to explore the waterfall room with its waist-deep icy water in the sun, the rain added an element of mystery to the hike.