The best part of my last Maui trip was sunrise at the top of Haleakala at 10,000 ft and then hiking the crater. It was May but sunrise at 10K was probably 33-35 degrees F.
All the best parts of my trips to Maui or Oahu have been when I've been as far away from Lahaina and Honolulu as you can get. Honolulu especially. It sucks. It's LA but humid.
I do want to hike some of Mauna Kea, see the lava tubes, etc... So at some point I probably will end up on the big island...