The baseboard along the stairs of our house shrank and pulled away
from the wall during the winter months. Now that it is warmer and
more humid, it is slowly expanding and the space between it and the
wall is shrinking. I understand that I can caulk the top of the
baseboard to the wall and the caulk should have enough "give" to it so
that it can handle the weather related expansion/shrinkage of the
baseboard. Is this right? If this is correct, when is the best time
to do the caulking?

Thanks,
-Jane