This is a big milestone, and is the end of a sensitive time for grapevine development.
Temperature, rain, wind, frost, pollinator health can all impact berry set.
Most of the potential in terms of berry/cluster size and amount is set in the prior year (especially during the late growing season, when bud cells are formed).
How much of that fruit comes to be is dependent on the current Spring conditions, and is evident with berry set.
We had a late (mid-April) frost that hit some vineyards in the valley (actually, in the entire state) harder than others.
As you can see, the berry set in our estate is pretty healthy, since conditions were not difficult locally. Some wind, but obviously not enough to do significant damage to the flowers during bloom.
We have a grower in Coombsville who suffered more frost damage, which will likely affect shoot growth more than berry set, but that site is late, and hasn’t gone through berry set yet.
Overall, however, what I am observing looks like a healthy, average crop for the valley.
Time will reveal more, of course.