Here's the post I'm maintaining: When will Mt Whitney switchbacks open?
Compared to 2017, there is less snow, and in that year, July 14 was when hikers started using the switchbacks. Also, note that the Crabtree water content for April peaked at 60% of the 2017 level. Crabtree is just west of Mt Whitney.
I am pretty sure by July 10 this year, you will be ok to go on the switchbacks.