I have been researching this as well, we arrive Jan. 26th. And what I've come up with is, you can't really tell until you get close enough to have a 10 day or similar forecast. It is just too unpredictable.
In general what I can see is it is usually mid 70s to low 80s daytime, 50s at night. But could drop to 30 you just never know.
As of now I'm planning layers. Some short sleeve, some long sleeve, a few jeans and some capris, hoodies or light jacket. If the forecast shows really warm then I'll pack shorts as well. I've seen alot of posts to say pack a shortsleeve in packback, wear a long sleeve with your hoodie/jacket. Most times the hoodie will come off and you will be good with long sleeves and pants, but have the short sleeve in case the sun makes you feel too warm.
Since I'm coming from NJ, I'll have my winter coat, gloves, etc if it does get cold.