Trying to make a program where on time base, in the morning set the temp to 'X' and from past X time make it "Y' lowering the temp until returning to the time where 'X' gets switched?
What have you tried so far ?
Have you tried sketching out the logical flow of the program on paper yet ? How does it look ?
If you have code started, then share that- give us a basis to help you from !
How much drift are you willing to accept?
On a Bs2 I'm guessing, you'll need a time keeping IC, like the DS3231, I2c but there is a program for the DS1307.