The time for salatul ‘id begins from the time the sun is three meters above the horizon until the sun reaches its meridian.
Ahmad ibn Hassan al-Bana’ records that Jundub said: “The Prophet prayed the ‘idul fitr prayer while the sun was [approximately] six meters above the horizon and the ‘id of the sacrifice while the sun was three meters above the horizon.”
Ash-Shaukani says: “That is the best of what has been related concerning the specific time of salatul ‘idain and the hadith shows that it is preferred to hasten in praying salatul azha and to delay the salatul fitr.”
Ibn Qudamah says: “It is a sunnah to pray salatul azha early in order to allow more time for the people to perform the sacrifice, and the salatul fitr is to be delayed in order to give people time to pay zakat al-Fitr. I know of no difference of opinion on this point.”