Weather here in Hawaii is quite a different experience that I ever had on the mainland or in the UK. Back there, if there was sun, rain, or clouds, it extended for the entire region, at least for miles around. But here that's not the case. The weather can be one way in the farm and totally different 5-10 miles down the road. We have a running joke here that if it is raining, people will say that it's a nice day to go to the beach, because often times it will be dry and sunny along the coast. So if you ask, is it sunny during the winter, you need to specify the exact location. It may usually be sunny and dry most of the time in my town, but often rainy and cloudy 10 miles away on my farm.
Some parts of Hawaii are mostly sunny year around, with only intermittent passing storms. Other locations are just the opposite, overcast and rain most the time with intermittent sunny days. My main farm usually has morning sun, afternoon clouds. By contrast, my seed farm location often gets mostly sun all day long. And these two farms are only 5 miles apart. But "J", unlike Washington state, Hawaii doesn't have long periods or seasons of overcast skies.
People moving to Hawaii need to do their homework. Weather conditions can vary considerably from one location to the next. And people's individual preferences can vastly vary. What I would consider acceptable rainfall or sunshine, another might deem it too much or too little.
And to make things more difficult to predict, Hawaii weather is cyclic. We see years of drought interspersed with wet years. That means that some years get lots of full sun days, while wet years see strings of cloudy days in a row. And to top that off, we are an island out in the ocean, thus brief isolated squalls can pass through just about any time.
Where I live, we see enough sun year around to be living on solar off grid. BUT, for years like this one, I need a generator because we just went through a month of rain. But generally, I get enough sun year around. Now......if I lived in Volcano or Mountainview I would want to be on the grid because of the lack of daily sunshine there.
So "J", I'd say that yes, the sun shines well during the winter in Hawaii. In fact, the nice tropical weather lures plenty of tourists here from November to April.