How can I keep the temperature in the basement the same as the second floor?
The thermostat is on the second floor and keeps it warm enough there, but the bedrooms in the basement get cold long before the furnace kicks on. Can another thermostat be added in the basement?

Any help is appreciated. Thanks

You need to add heat runs in the basement if you want heat in the basement. Contact a local HVAC professional to check your situation and to see if it is possible to add the required heat duct or registers.