User blog comment:LucasH181/Too busy :(/@comment-24200325-20150801100413/@comment-24693229-20150801100819

3 months are calculated according to 4 periods: January-March, April-June, July-September and October-December.

So, you have to make at least 20 edits during the third period of 2015 - from July 1 to September 30.