No. of Cyclones that hit TN during December in the last 50 Years : 7
Average Cyclone Frequency : Roughly once in Seven Years
Years that had Cyclones hitting TN in December : 1964, 1967, 1972, 1993, 2000, 2005, 2011
Last Cyclone to hit TN in December : Cycone Thane in the year 2011 http://en.wikipedia.org/wiki/Cyclone_Thane
Most Destructive Cyclone : Dhanushkodi Cyclone in the year 1964 http://en.wikipedia.org/wiki/1964_Rameswaram_cyclone
Cyclone Fanoos in the year 2005 took possibly the straightest path ever taken by a Cyclone in the Bay of Bengal. Dead West all the way until it hit South of Nagapattinam.
No. of Depressions that hit Tamil Nadu during December in the last fifty years : 6
Most Famous depression : Very Severe Cyclone Madi which dissipated and crossed TN as a depression in the year 2013
Edit: It has been pointed out Cyclone Fanoos became a Depression just before landfall as per the 2005 End of Season summary prepared by IMD. The Cyclone EAtlas still shows it as crossing the coast as a cyclone.