Imam al-Shafi'i (may Allah have mercy on him) says: The adhan is not given for any prayer other than the morning prayer except after its time has come in, because I do not know of anyone who has related from the Messenger of Allah (peace and blessings be upon him) that he gave the adhan for any prayer before its time other than Fajr; and we have not seen our muezzins give the adhan except after the time of the prayer has come in, apart from the Fajr prayer.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1808