I'm in LA - not quite Anaheim, but similar enough for purposes of this question. In Southern California especially, we don't really have humidity (especially with the heat wave we've been having - it's 80 degrees with 6% humidity right now!). So while you might be a bit warm standing in the sun, the shade is usually ~5-10 degrees cooler. Nights are definitely cooler, anywhere between 30 to 50 degrees depending on that day's weather.
California weather changes a lot. On Monday, the high was around 45 degrees. Today, it's in the 80s. So make sure to keep checking and bring lots of layers and variety of clothes - like if it says the weather will be in the 50s-60s, bring a pair of shorts just in case.