To Remain Junub until Morning Adhān

Fast Invalidators
To Remain Junub until Morning Adhān
During Ramadan month, if someone becomes junub, he should make ghusl before morning adhān. If he does not make ghusl before adhān, his fast is not valid. The same rule applies to qaḍā’ fast of Ramadan even if it is unintentional.
Source: Hadana adopted from the Istiftaat of the Grand Ayatollah Khamenei