At this time of year it could just be condensation boiling off in the exhaust system, but that usually fades after a good run. White smoke usually means moisture (including coolant), blue is oil, black is fuel/misfire.
One sure sign is coolant consumption -- if coolant is mysteriously disappearing without leaving puddles under the car, then maybe it's going out the tailpipe. A check of the plugs may reveal which cylinder is involved. A significant leak into a cylinder will usually cause misfire issues, and may cause hydro-locking, especially when attempting a restart when hot.