In the Fall and the Winter it is a hit and miss type of thing one week will be beautiful and the next will be cold and miserable. There is no way to tell. One of the first things that you should know about the weather in Hawaii is that no one knows about the weather in Hawaii. It changes so quickly that you can sprain your neck watching it. If you are planning a vacation remember that it is never like this.
Every year is different and every day is a surprise.
The big question on the Island is how often do the weather guys have to buy a new dart board, because it can be anyone's guess. But watch out, the weather here can get vicious so be prepared. Bring a rain coat if you are coming here around winter and prepare to get wet at least some of the time. Mostly don't let it get to you. Even the bad weather here is beautiful.