First thing this morning it was around 27 degrees outdoors, but with the compost cooking in my 10x12 unit, it was 40 degrees in there. That's sufficient overnight temps for me. The only sprouts I have in there so far are some sedum, but I'll be looking out for new arrivals within days, most likely. As long as we don't go below 20 anymore I should be in good shape. The sun is out a bit right now, so I have a big fan running and it's a lovely 70 degrees inside.
I'm hoping to spend an hour or two out there today.