Here is a summary:

  • 4 weather changes for crops to reach middle state
  • 4 more to fully grow
  • 4 changes for crops to die (12th changes in total) 

Weather changes which are taken into consideration: from Fair to Shower and vice versa. Weather is depending on the season. For example, it's only 1 weather change at Winter :) 

 

Detailed observation with screenshots:

Here is a calendar took as example from YO server with planned dates

and this is how crops will change their state from day to day

  • March 15th