My understanding of El Nino and Californian weather is that it's a winter effect. Most (but not all) El Nino years have above average winter precip, especially in SoCal. It also makes a Pineapple Express storm more likely, which is one of the ways it pushes up the average. We usually don't drip our way out of a drought, it's common for it to be broken by a big wet winter, so maybe this is it.
I don't think El Nino matters too much for summer, but I could be wrong. It may increase monsoonal moisture, which could result in more Sierra thunderstorms, but that's pure speculation on my part. I've never seen any data correlating El Nino and California summer weather.
