Is it permissible to give a portion of Zakat in Ramadan (as an advance payment) if its original due date passed several months before Ramadan, with the intention of paying the full amount in Ramadan in the future?

The time when Zakat becomes obligatory is upon the completion of a full lunar year (hawl) on possessing wealth that reaches the nisab (minimum threshold). Zakat must then be paid. It is permissible to pay Zakat in advance of its due date if there is a need, such as the presence of impoverished people or calamities, but it must be paid in full. A Muslim must know the lunar months because they are what is intended by Allah's saying: "Indeed, the number of months with Allah is twelve months in the Register of Allah," and by which acts of worship are precisely timed.