June July Aug is Best for wind and you can get decent swell too.. there is generally always a wave to ride.
I had my honeymoon in Honolulu in June 2002 (good timing) my wife enjoyed the shopping etc while I enjoyed the waves at diamond head.

I took my lightwind 88L wave board and 5.8-4.7 sails - perfect for the conditions.
There are other places to sail on the south coast of Oahu, toes was good but you will need to watch the shallow reef.