Pedro’s name day is January 16, the feast of Peter.
Churches that follow the Old (Julian) Calendar keep the same feast on January 29 of the civil calendar. See everything commemorated on January 16.
The saint behind the name

Peter
January 16, Martyr, Πέτρος
On this day the Church venerates the precious chains of the holy Apostle Peter. The Acts of the Apostles relates how Peter, imprisoned by Herod and bound in chains, was freed in the night by an angel of the Lord, the chains falling from his hands as he was led out past the sleeping guards.
Also celebrating on January 16
These names share the feast, many of them other forms of the same name:
Petros, Pietro, Pyotr, Pete, Peter
What to say on a name day
The Greek wish is Χρόνια Πολλά (Chronia Polla), “many years.” A call or a short message on the day is what people remember. See name day wishes you can send and what a name day is.