Not quite - they do film back to back seasons to save on production costs.
Both seasons for this coming fall and winter will be in the can by the time the Fall Season starts.
Figure 40 days, around 10 days break and another 40 days totals 90 days.
So they should start filming right quick........
http://www.realityblurred.com/realitytv/archives/survivor_27/2013_Apr_08_returnees-families