What is a Zakat anniversary?

Most people don't know when they are liable to pay Zakat. One of the main elements in becoming liable to pay Zakat is called Nisab. Nisab is the minimum threshold of wealth a person must own at which Zakat becomes payable. Once Nisab is reached and a person stays above the Nisab an entire lunar year without going below it they become liable to pay on that specific date (Hijri date). For example, if someone goes over the Nisab on the 20^th of Ramadan and they stay above it the entire year they are liable to pay Zakat on the next 20th of Ramadan or before it.