Just some data from SDN for you all:
Last cycle (2019-2020):
Wednesday, January 29: First round of A’s
Thursday, February 27: 1st WL movement
Thursday, April 9: 2nd WL movement
Monday, May 4: 3rd WL movement
Monday, May 11: 4th WL movement
Friday, June 5: 5th WL movement
Thursday, June 11: 6th WL movement (not sure about this one)
Current cycle:
Friday, February 19: First round of A’s
Thursday, March 25: 1st WL movement
Given the unprecedented nature of this cycle, I don't think any predictions can be made regarding when exactly the next WL movement will happen (although I will say that both May WL movements were on Mondays 👀). But unless last year there was just an abnormally large amount of WL movement compared to any previous year, I think we can expect a good amount this cycle.