For previous seasons that premiered in February or March filming started:
Season Film Start Location Film End Location Length Premiere Date
TAR 16 2009-11-28 Los Angeles, CA, (Vista Hermosa Park) 2009-12-20 San Francisco, CA, (Candlestick Park) 22 2010-02-14
TAR 14 2008-10-31 Los Angeles, CA, (Los Alamitos Naval Base) 2008-11-22 Maui, HA, (King Kamehameha Golf Club) 22 2009-02-15
TAR 11 2006-11-20 Miami, FL, (Charles Deering Historic Estate) 2006-12-17 San Francisco, CA, (SF Botanical Garden) 27 2007-02-18
TAR 9 2005-11-07 Morrison, CO, (Red Rocks Amphitheatre) 2005-12-03 Morrison (Denver), CO (Red Rocks Park) 26 2006-02-28
TAR 7 2004-11-20 Long Beach, CA, (Queen Mary Museum Ship) 2004-12-19 Fort Lauderdale, FL, (Bonnet House) 30 2005-03-01
TAR 2 2002-01-08 Pahrump, NV 2002-02-05 Sausalito, CA (Murray Circle on East Fort Baker) 28 2002-03-11
If you throw out TAR 2 as an anomaly, using past seasons as a guide, I would guess sometime between October 29 and November 27 to start.