The question of when a person can submit the I-485 to apply for a green card is one of the trickier aspects of US immigration law to understand. Since October 2015, the Department of State has published two charts for the family-based categories, and two charts for the employment-based categories. The first chart is called "Final Action Dates" and the second is called "Dates for Filing." The dates in the final action date chart are the priority dates that will actually be current for that particular month. The dates in the dates for filing chart are the priority dates that Department of State thinks will become current in the coming months.
To make things even more confusing, each month after the visa bulletin is published, USCIS updates their website to indicate if they will accept I-485s based on the final action dates chart, or based on the dates for filing chart. Over the years, we have found that USCIS usually says that they will only accept I-485s based on the final action dates chart (meaning the top chart, where the dates are actually current). However, for October 2018, USCIS has indicated that they will accept I-485s based on the dates for filing chart. This means that if your priority date is current per the dates for filing chart, you can file your I-485 in October. For example, if you have an employment-based permanent residence petition, you were born in India, and you fall into the EB-2 category, if your priority date is before May 22, 2009, you can file the I-485 in October. If your priority date is current per that chart, we highly recommend that you file the I-485 as close to October 1 (but not before!) as possible. That way if for any reason USCIS changes their minds mid-month, your I-485 is already filed.
If you need assistance determining if your priority date is current, or if you need help filing your I-485 application for permanent residence, please contact our office at firstname.lastname@example.org, or at 804-396-3412. Emily Sumner is an immigration lawyer in Richmond, VA but we serve clients throughout the US and around the world. We look forward to helping you!