Sheikh Salman al-Oadah
It is permissible to pay Zakah on wealth that has been in your possession for less than a year. Some scholars have drawn this meaning from the hadîth where the prophet (peace be upon him) said: “As for al-`Abbâs, it (his Zakâh) is upon me and the likes of it with it.” [Sahîh al-Bukhârî (1468) and Sahîh Muslim (983)]
Scholars explain that al-`Abbâs had paid the Zakâh on his wealth for two years. There is a weak hadîth that states this meaning more clearly. It reads: “Indeed, we have taken from al-`Abbâs last year the Zakâh of this year.” [Sunan al-Dâraqutnî (2/124)]
In brief, it is permissible for you to pay your Zakâh before it becomes due. Indeed, it is permissible for you to pay Zakâh for the coming year as well. This may be a good thing to do if the Muslims are in need.
A person can make the month of Ramadan the month in which he pays all of his Zakâh. He does this by looking at all of the wealth in his possession and paying the Zakâh on it. Paying Zakâh in this way in Ramadan is good for two reasons:
1. Paying the Zakâh all at one time simplifies matters greatly. Otherwise, it is very difficult for a person to determine for all the money in his savings precisely when it came into his possession and then pay the Zakâh upon each amount as it becomes due.
2. The month of Ramadan is a month of special virtue. It is the month of generous rewards where the blessings of deeds are multiplied. It has been related that `Uthman even called Ramadan “the month of Zakâh”.
Source: Islam Today