Clue: Smur in Glasgow or Dundee coming up (4)
Answer: DROW
Explanation: Definition: Smur
Hidden in reverse of glasgoW OR Dundee; Chambers gives "fine misty rain" for "smur" and " drizzling mist" for DROW: there may be a subtle distinction between the two: in any case, both are familiar to those of us who regularly visit Scotland (for obvious reasons I have had to cancel my next visit, which was due in May)