The Short Answer
The answer is that it depends on each person. The right time to pay Zakat is at its prescribed due date, which a Zakat Calculator can help determine.
Zakat, the yearly obligatory alms on the growable wealth of Muslims, comes due on the profit of eligible wealth once a lunar year (called a hawl), provided it reaches its specified threshold. A wealth stream’s Zakat Due Date (ZDD) depends on the kind of wealth it is. (See the Zakat Calculator)
Zakat-eligible (“Zakatable”) wealth generally falls into two categories: (1) growth wealth and (2) earth yields and windfalls. Each kind has its own distinct ZDD. (See Is Zakat Due on All Wealth? and also What Requirements Qualify Wealth for Zakat?).
Growth wealth includes money, business assets, and livestock. Earth yields and windfalls cover crops, honey, agricultural produce, extracted minerals, and found treasure.
Payers remit their Zakat on growth wealth after 12 complete lunar months (354 days) passes on one’s sole ownership of them. One calculates the ZDD of each wealth-type’s Zakat from the date one acquires it.
Since earth yields and windfalls themselves constitute the “growth” and “profit,” one pays Zakat directly from them at the time of their harvest.
Can one set one’s Zakat Due Date arbitrarily?
No. The Prophet, on him be peace, established Zakat’s payment schedules, as stated in the previous question. His successors (khulafâ’, caliphs) in leadership over the Muslim Community abided by his practice. Muslim legal scholars have near unanimity on these Zakat Due Dates.
One can pay Zakat in advance, however, even by years, through calculated estimate, making up for deficits at its actual ZDD. (See When Is Zakat Due?)
Is there are more desirable time to pay Zakat?
Yes. Ramadan is the best time to pay Zakat because it significantly multiplies the divine reward of one’s payment.
Remember that Zakat is an obligatory act of worship, the Third of Islam’s celebrated Five Pillars, in fact. As such, it brings about immense spiritual recompense for its payer, even though it is an obligation.
Allah, the Sole Creator of the Heavens and the Earth, who will call human beings to judgment in the Afterlife, chose Ramadan, the ninth of the 12 lunar months, as a fasting month (Islam’s Fourth Pillar). He hallowed it as a special space in time wherein He will recompense returns on the believer’s good deeds, obligatory and voluntary, in quantities that significantly exceed His normative reward for these good acts themselves at other times.
Muslims have from the first prefered to pay their Zakat in Ramadan.
One can adjust one’s payment of Zakat to Ramadan, provided Ramadan is not beyond one’s ZDD for existing wealth. Then when one’s ZDD comes, the Zakat payer can reconcile any difference in the due Zakat payment. This can be done at any preceding date with calculated estimation of one’s due Zakat, and then precise adjustment. (See Is Ramadan the Best Time to Pay Zakat?)
What begins one’s Zakat year?
On the date one’s solely owned, individual wealth-type crosses its specified niṣâb threshold, one’s Zakat calendar begins. Again, on agricultural, extracted, and discovered wealth, one pays Zakat upon harvest. (See Nisab and Zakat Calculation in a Nutshell).
The Prophet, on him be peace, set the niṣâb values for all types of Zakatable wealth. For personal, business, and discovered wealth, he set that level for each at the equivalent of our current measure of 85 grams of pure gold (approx. 3 U.S. ounces). (See How Is Zakat Calculated on Wealth?)..