We have this stuff called June Gloom. That means it's often overcast, but don't let that make you think it'll be cold, because it probably won't be. Actually June's an iffy month weather-wise. Sometimes it's rather warm, other times it's on the cool side. Even though the gloom will make you think it's going to rain, it probably won't (at least not that close to the coast). My suggestion for what to pack is a little bit of everything. You didn't mention if you're coming in early June or the latter part of the month, because the closer it is to July, the warmer it will be. Here's an example of how strange June weather can be in CA--on June 1 last year I was at the Pond in Anaheim for a skating show. It was really hot standing outside waiting to get in--about 90 degrees I think and they didn't let us into the building until 20-30 minutes later than normal (should have been in at 2 but it was closer to 2:30). The next weekend I went to DCA for Super Soap weekend (not sure when that'll be this year) and it was cloudy and overcast and a bit on the cool side. The first day I wore shorts and was a bit too cool. I wore jeans the second and was much more comfortable. The next weekend it was probably hot again. But, even if it's cloudy, wear suncsreen, because the uv rays still get though the clouds that time of year.