I just got back from 7 days in Yellowstone guiding in the Lamar Valley.  The first half of the trip was cold, wet and a bit windy while the second half was mid-seventies and sunny.  The poor weather made for some amazing skies and moody sunsets and even lightning on my first night.  The fishing on Soda Butte and Slough Creek was quite good despite the as to be expected crowds.  I had one day on the first meadow of Slough that was slow, otherwise it was tons of fun with hoppers, baetis and green drakes.  I'll be posting pics the next few days...

Above the Ice Box Canyon on my first night I was greeted with a little weather:

The Lamar River:

Last light on Soda Butte: