I can tell you what months to stay away. AUGUST! Lots of tourist from Japan and later part of August, Koreans comes down along with the continental United States because of school summer vacation!
Late October till mid-March is the usual rainy season in Hawaii. End of March is end of school for Japan, and second week of April is Japan's Golden Week Holiday.
I am mentioning this because of the hotels in Waikiki usually become booked by the Japanese tourist coming here with their children during school break.
April, May, June, and July are better. September and beginning of October is grand, because the beaches are less crouded in Waikiki, and October and November, we have fabulous sunsets.
And when we have our drough season during el-nino, you can enjoy beautiful beach weather during Christmas and New Years! Something to behold! Enjoying the beach ON Christmas DAY!
The photo below of Diamondhead, was taken by me right on Christmas Eve 2009 !