I just got back from a business trip to Oklahoma City.
As others have said, the weather out here is all over the place. This past weekend it was in the high 70s, right now it's mid 60's, and it's supposed to rain by this weekend. You really have to just stay tuned to the weather channels and dress accordingly.
Having said that, once the sun goes down expect it to be rather cool. In the sun, if it isn't windy, it can be quite nice. A couple of weekends ago, I was driving along PCH in Huntington Beach and could smell the wood smoke from the bonfires people were having on the beach. It was about 65º. It was around 5:30 or so. You might want to keep that activity in mind if it's warm enough. The grocery stores here usually have a bundle of wood you can buy.