Tourists in Southern California are frequently disappointed in the weather this time of year. Most people would expect this area to full of bright and sun shiny days; it is summer after all.
We have instead of sun shine is 'June gloom'. The gloom is set in particularly heavy today; it's about 1:30 PM, it hasn't burned off yet and there are no signs that it's going to happen any time soon.
So, if you plan on visiting Southern California, don't. But if you insist, you should come some time after the middle of July or so if you want to avoid the June gloom.