Most fares from the East Coast begin in the upper $2000 range and work their way up into the low $3000 area. Fares from the West Coast range between $3500 and the low $4000 area.
As is typical with SWISS, they do not publish any of the terms or conditions of the fares in any obvious place, so it’s hard to tell how long the fares will be available and what other conditions may exist.
Your best bet is to use something like ITA Matrix or Google Flights to see their fares illustrated in months vs. just days if you search via SWISS.com. What I did see was the fact that the best fares were available when traveling on Monday, Tuesday, or Wednesday.