From Runner's World interview published a week ago:
Runner’s World: How are you feeling?
Dathan Ritzenhein: Doing good. Just got back down to Florida. This is the third trip we’ve taken down here this winter. Keith and Kevin [Hanson] always have everybody come down for 10 days before going straight to Boston, to get ready in case it’s a hot year, as it seems to be every four or five years there. It will be nice to have good focus for 10 days.