Wonderful climb. Extraordinary vistas all along the route. Had a beautiful clear day. Even saw huge plumes from Santiaguito! On the return, hiked down to the hot springs and saw a rare Quetzal bird along the way.
Climbing Zunil is great fun. One of my favorite sunrise views in Guatemala is from Santo Tomas (the volcano connected to Zunil). You can see into Lake Atitlan to the east and into the erupting Santiago Volcano to the west. I added a topo map to the images section of the volcano in case anyone is interested in climbing.