How it works (Example):
In the finance world, quarter 1 usually spans January 1-March 31; quarter 2 usually spans April 1-June 30; quarter 3 usually spans July 1-September 30; and quarter 4 usually spans October 1-December 31. However, companies may have their own quarterly calendars.
The Game release calendar follows this same pattern, and each developer follows the same Q1-Q4 pattern as the rest because if they didn't they'd only ope themselves up to attack from their customers for not being clear enough on dates for, well, anything. This logic leads me to telll you, you don't need an answer from an FDev employee. The game will be out by the time July arrives, because if it isn't and they tell people their Q1-Q4 calendar works differently from everyone elses, they will lose a big potential playerbase because of poor communication.
Just think how much of a PR nightmare it would be if your Q1-Q4 calendar worked just 1 month differently to everyone elses.
Q1: Feb-Mar-Apr
Q2: May-Jun-Jul
Q3: Aug-Sep-Oct
Q4: Nov-Dec-Jan
Developer: "Good news everyone, we're on schedule for a Q4 release!!!"
Customer: "Excellent, on time for Xmas no doubt!!!"
Dev: "...."
Cust: "..."
Dev: "Yup... Q4"
Cust: "It's New Years guys..."
Dev: "Oh.. I meant our Q4... You know... End of January"
Cust: "Oh cool... We're skint. Might pick it up in Q3. Or Next August according to OUR calendar..."