Polish federation announced today that one of tournaments will be in Poland and then they also published the schedule of Poland in the 2019 edition of VNL.
From this we can tall that like this year the "weekends" for women are Tuesdays, Wednesdays and Thursdays and preliminary phase will start on May 21st and end on June 20th.
21-23 May (Poland, Opole): Poland, Germany, Italy, Thailand
28-30 May (Netherlands): Netherlands,Brazil, Bulgaria, Poland
4-6 June (Belgium): Belgium, Serbia, Russia, Poland
11-13 June (China): China, Turkey, USA, Poland
18-20 June (Korea): Korea, Dominican Rep., Japan, Poland