Dates in May 2000:

4/5 May  -  light snow early, cirrus later, high RH (.70%) until midnight
5/6 May  -  clouds late (~9 UT)
6/7 May to 10/11 May  -  no observing due to weather (clouds & snow)
12/13 May  -  clouds in data, ~04:45 UT onward
13/14 May to 15/16 May - big snowstorm!
24/25 May  -  clouds most of night
31 May / 1 Jun  -  cloud & snow in early morning