Nice looking bonsai! I have a Hinoki Cypress as well, this is the best care guide i have found: www.bonsaiboy.com/catalog/hinokicare.html from what i understand they like the cooler temperatures
Don';t trust the guidelines from bonsaiboy. The guidelines are copy/pasted from other trees and they have simply replaced the tree species - so they are very generic and NOT specific for this tree.
"A
[tree species] Bonsai is a living miniature tree and not a house plant; therefore, your bonsai must be maintained in a cool/cold environment during the winter season. As a guide, around Thanksgiving Day it is time to prepare your Bonsai for its winter dormancy period which should last approximately three (3) months"