Can't say how the weather would be better one way or the other - would depend on current weather patterns at the time of the cruise!
We did Hawaii to Ensenada in April. We live in Ohio and wanted time to relax after doing all of the Islands. It worked out well for us. 4 days at sea was just wonderfully relaxing. (We only experienced 1 or 2 days when it might have been too chilly to sit out on the veranda.)
Hawaiian cruise will be enjoyable no matter which way you go!