Fished Yellowstone NP and Rock Creek over the last week with excellent success. As expected, the weather this time of year was unpredictble to say the least. For the first 3 days the weather was warm (about 75) an sunny while the last two were cold (low 40's) and rainy/snowy. I fished dries exclusively during the warm spell and had excellent sucess on the Gibbon and the Canyon section of the Firehole with PMD's ,Caddis, and smallish stonefly patterns (sze 8-12). Once the weather flipped (nasty cold driving rains) I fished the Firehole (sections immediately above the Canyon) and the Madison exclusively and had great success with BWO emergers and dries. Overall, the fishing was great for this time of year. I only fished about 30% of the time while in the park and spent the rest of the time hiking and enjoying the wildlife with the wife. Rock Creek was a bit of a disapointment. Heavy rains the day before I arrived and run-off made the river pretty high. However, I was able to land a 6-10 westslopes, cutbows and rainbows on a a variety of salmonfly and goldenstone patterns.