Weather is so variable
. I walked the Primitivo in early mid May 2019. Nearly daily rain, mud, very cold and for the beginning of the Hospitales stage the fog was so dense at one point that I couldn’t see the Peregrino in front of me yet I could touch him. Four of us formed a small group for this stage, and eventually the fog on the mountaintop cleared though the fog persisted below us and all around. We were freezing, at one point it seemed I wore everything I brought. The poncho kept flying over my head and secured it with a string leading to my very convincing Friar Tuck impression.
Still awesome and still one of my all time favorite stages on any Camino.
If possible for you I would choose September instead of July for the same reasons described above.