Martin,
I can't comment for CPC, but I can give you a little insight about irrigation practices on the central coast of California.
From Monterey to San Francisco there is basically no rain from April to October, so golf courses are totally dependent on irrigation during those months. That being said, the ocean has a very moderating effect on the weather. Temperatures range in the 60's, fog or overcast is present many days (like today) burning off mid-morning, sometimes staying all day. Summer, as many know it, is the end of August, September and October with glorious days and temps in the 70's, maybe an 80 here or there. It rarely reaches 90 on the coast and when it does, it's front page news.
At Half Moon Bay, 60 miles north of here and right on the ocean, I watered fairways once or twice weekly until September when I had to increase the frequency. Where I am now, a mile inland and 30 miles north of Monterey I water every other, to every third day.
Of course different courses have different soils, microclimates and water quality, all of which would affect the irrigation regime.