I might go today (and if not today, then definitely tomorrow). I'll report back on the crowds.
Weather wise, it's cold (for southern CA!). It's about 50 degrees right now, forecast high for today will be 58.
When the sun is out, it feels warmer than it is, but as soon as the sun sets or some clouds roll in, it gets chilly.
Pack for cool weather during the day, but COLD weather once the sun sets (around 5pm). As a rule of thumb, plan for short sleeves during the day with a light sweater or jacket on hand. Rather than paying attention to the HIGH of the day, look at the LOW. That will give you an idea of how much covering you will need for the mornings/evenings.
Pack pants, short sleeves, long sleeves, sweatshirts (and jackets if you will be out/about in the parks at night).
You can't go wrong with layers. Unfortunately, this time of year, you have to bring along pretty much your entire wardrobe.
