It really depends on the species. Jackson's and veileds can go down into the 50's or lower at night. I would only allow panthers to go down into the mid-60's at the coolest.
During the day 80 - 90s, at night at least 50 - 60s. I live in NH and we are beginning our fall and winter seasons. It gets really cold here at night and really dry. I have to keep up with the humidity levels here during the day, at night, not so much. My humididty falls well below 30 on my hygrometer during the day. Without a combination of a humidifier and misting I think it would be too dry. I am not constantly pumping high levels of humidity in the enclosure, just enough to exceed 30 percent.
damn ill work on gettin mine closer to the 70's ands mid 60's..i probably won't run the heat this winter.. probably still won't get under 70 in the house.