This gets discussed every few months here on CN and opinions differ. Probably no need to rehash this topic, it's been done many times already (search can be your friend).
If the humidity is high and the temperature difference is also significant (meaning cold outside) then I will "bag" my scopes in plastic before taking them inside and then I open the bags on the next morning to allow outside air to reach the optics. On other nights I just place a good dust cap over any of the exposed ends of the scope. On really bad nights I may throw a couple of packs of desiccant into the bag before it is sealed.
Of course, this requires that the scope is already dry before you place it inside of the bag. In the latter case you won't/can't get any more condensations inside of the bag once you bring it inside because the temperature can only go up, since the relative humidity inside of the bag can only go down as the temperature of the "bagged" air gets higher. However, if the scope is already wet when it is outside then you need to get it dry as quickly as possible and that may require different treatment.
As for having low humidity inside the house during the winter, during a winter Santa Ana condition in California you may have higher humidity in the house than outside, so bringing a cold scope inside may cause moisture to form on the tube and optics.
Edited by james7ca, 19 November 2017 - 09:20 PM.