I'm going to add here... just remembered, we drove around on Sunday and saw tons of out-of-towners downtown. It was 75 with very low humidity, and brisk wind. If you are site seeing downtown, the buildings can block the sun, and it can get chilly. I recall seeing that most site-seers were wearing long pants or jeans, with short sleeve or sleeveless top, and comfortable flat shoes. Alternatively, shorts/clams/skirt, with long sleeve top/cardigan.
With this type of weather (what I tend to think of as "California" weather), it seems either legs need to be covered while arms are bare, or legs are bare but arms are covered.
I would still, however, pack flexibly for contingency that your week is hot and humid. Because it might be. Can't predict.
