Thwarting the Fry King
Python 2 (228 209 208 207)

(not counting the last newline)

import time
s=time.strptime
f=raw_input().split('*')
t=s(f[2],"%d/%m/%Y")
if t[1:3]in[(2,29),(7,21)]:t=s("%s%s"%(t[0],t[7]-1),"%Y%j")
print"NNSSWEWE"[(t[7]+s(str(t[0]),"%Y")[6]-int(f[0])-int(f[1])*2+3)%4::4]


Edits:


substituted variables that were used only once, further golfed the print statement.
Removed the space after print as isaacg suggested.
Changed from time import*;s=strptime to import time;s=time.strptime to shave off one extra byte