Possibly powdery mildew -- it can look very strange on some rhodies.
.
Please post a picture of the undersides of the leaves.

I hadn't thought to look at backside of leaves but definitely doesn't look good. Any thoughts what's going on?

Powdery mildew is a real possibility, but there are many other maladies which can look much like the photos: oedema, fungal leaf spotting, and several more. Since you live in WA where there are many rhododendron nurseries and experts someone should be able to identify the cause if you can bring them one of the leaves for examination. Your county extension service or state agriculture department are other possibilities.

The very mild yellowing you are getting on the top surface between the green veins is chlorosis. This can be caused by many things, but is usually a symptom of acidity that is too low or too high, resulting in an iron deficiency. In most of the world the problem is low acidity, but in the Pacific Northwest there are regions with very high acidity.

Some other causes of chlorosis are potassium deficiency, calcium deficiency, iron deficiency, magnesium deficiency, nitrogen toxicity (usually caused by nitrate fertilizers) or other conditions that damage the roots such as root rot, severe cutting of the roots, root weevils or root death caused by extreme amounts of fertilizer.

The yellow spotting that is brown underneath is something else. Sometimes it is genetic. Usually it is either a fungus or virus.

Here is a link that might be useful: Common rhododendron problems & solutions

I just checked one of the leaves and yellow spots in front line up exactly with spots on back

I have been trying to get location and hours for lical naster Gardener office to take a leaf for analysis but I keep getting passed onto phone number after phone number getting voicemails.