Thank you for all your replies gentlemen!
Yes, the book says that only significant changes should be stated. My question would then be; How much does the wind have to vary? 10degress and 5kts? Where is this stated?
And, how do you make sure that the information the pilot has is the latest? The ATIS the pilot has confirmed received might be outdated by the time he gets to the holdingpoint for departure and Im sure that most of the towercontrollers have other things to do than to update pilots on what Atis is valid.
Just seems like the easiest procedure would be to include wind with the take-off clearance.