About the same here in SW NE. I have a 60w bulb but I don't think it does anything except maybe help waterer . We have heated water in coop and that helps . Question do you vaseline combs to prevent frostbite? They're coop is 13 right now and their allowed out but prefer coop most of the day.Well...it got down to -18 last night here in South Dakota. Chickens were ready to get out in the run right away this morning...they seemed perfectly fine after a cold night with no supplemental heat!