We were on this year's Honolulu to Vancouver repositioning. As Deb says above, the weather, even at sea, was moderate. I took some heavier clothing and didn't need it. It was "sit out on the balcony" weather the whole trip, and pretty warm in Hawai'i.
One thing to note: the embarcation in Honolulu was the worst by several orders of magnitude that we have ever encountered. It was disorganized chaos, with no attempt at helping from staff, and in an un-airconditioned warehouse of a building with no air circulation, and with several hundred people all swirling around in the heat and humidity. It took over two hours to get to the head of the line, when there even was a line, and most of us were drenched in sweat and dizzy from the heat and the tension. I would never, ever embark in Honolulu again unless I knew that the situation had been remedied.