I see you're in Vermont. This comes up every year for us Northeasterners and those who reside in other cold parts of the country. Humidity levels in humidors go WAYYYYYYY down in the winter. As has been said, during the colder months of the year, when furnaces are blasting and drying up the air in your house, adding even more dryness to what the climate has already done, you need supplementation.
I keep a large plastic screw top that came off the container to a powdered food supplement in the humidors that need it, which is three out of my four desk tops. I fold a paper towel until it's small enough to fit into the cap, and pour a bit of distilled water into the cap. It gets absorbed into the paper towel, and I don't use so much that there's any left to spill in case I pick up the top and it slips out of my hand and falls back in. After a while, when the paper towel gets dry, I pour more water on it to wet it again. This goes on all winter. You'll need it. Depending on the humidor, levels can go to as low as 45-50% which will dry up your cigars badly and take them a long time to get back to smokeability.