I am in North County San Diego and use a drip system. I have it set on an irrigation timer for 1 hour per day and I use 1 gal/hr drip heads. So every day they get 1 gal of water. This worked well last year (the first for my hops) and I only gave them a little more water in the afternoon one days that it was really hot. I also check soil moisture very unscientifically, stick my finger in the mound
. If dry then I would give the extra water in the afternoon.
One thing to consider is mold/fungus. My timer is set to run in the morning to minimize wet soil at night. Which mold/fungus love wet-dark-warm enviroments. Just think of a lawn. If you water at night you get a mushroom field. So this in mind try to limit late day watering.