Depends on the historical demand for the flight(s) that Swiss has logged on comparable days going back a couple of years, which will be adjusted by current trends in the weeks immediately prior to departure.
So it's crystal-ball stuff to you (which is of course how it should be...)
You could of course chat up a friendly travel agent and get them to have a look at Amadeus' sales display to see if a) any of the lower buckets have limited (or no) capacity (which is a dead giveaway that they're expecting higher demand for higher revenue buckets and that the price is unlikely to degrade) or if all buckets are open for sale (which could mean that the final unconstrained demand will be less than the capacity and could mean that better deals are around the corner.