Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Zakat is payable when someone's net worth exceeds the appointed Zakat-payable amount (Nisab) and is continuously possessed over one lunar year. So whenever times comes for Zakat whether in Ramadan or other times, the able Muslim has to give it away. It is not permitted to delay its payment for more than two days or for any reason like paying it during Ramadan.
Thus if an individual delays the payment of Zakat more than two days or so, the obligation upon him to give it does not expire in time. Nor will it be dropped in case of a hazardous situation causing the loss of the due amount he has reserved for it within that period, according to Sheikh Khalil, may Allah rest his soul in peace.
The same view was endorsed by the scholar al Khurashi, may Allah rest his soul in peace, in his interpretation of Sheikh Khalil's analysis.
Accordingly, if someone's net worth is Zakatable, Zakat should be paid whether in or outside Ramadan. It should not be delayed for more than three days or paid in advance for more than one month time. And Allah knows best.