Better to arrive Petra for the night activity first. “Petra By Night” runs every Monday, Wednesday and Thursday, starting around 8.30pm and ending around 10.30 pm. Entrance fee is around 12 JD (as of 2014). Show takes about 1 hour. Be there early as walking takes around 20 minutes to the area where the show takes place. After the show, go to your hotel and visit Petra in the next morning. Full day is fine.
They tell that “Day-Visitors pay more than overnight visitor.”. They did not even ask this question to us. So we strongly believe that even if you are a day visitor, you will pay the same amount like the overnight visitors.
Daily entrance fee is quite expensive. It is around 50 JD (as of 2014). Night entrance is relatively cheap but also limited for 1-2 hours for the night show. You may not combine daily entrance with night show.
If you can speak Arabic, entrance is around 1 JD for you. Good fact for those who speak Arabic !
Driving from Amman to Petra is a hard work. Do this during the day as the lights on the road are not sufficient.