set wxcols c1 c2 c3 c4 c5 
where c1...c5 are the weather symbol colors
c1 (default color 2, red) :  thunder/sleet/freezing/hurricane [used in symbols 1-13,24-27,31-32,38,40,41]
  c2 (default color 10, green) :  rain/drizzle [used in symbols 3,8,12-18,24,26-30,37] 
  c3 (default color 11, blue) :  snow [used in symbols 4,9,19-23,37] 
  c4 (default color 7, yellow):  fog [used in symbol 34] 
  c5 (default color 15, gray):  blowing snow/sand/smoke [used in symbols 33,35,36,39] 
Run the script wxsym.gs to see how the colors of the various symbols are implemented.