There is a distinct peak wedding season in Hawaii during the summer months (starting in March all the way until October). If you are planning a destination wedding in Hawaii, get ready to spend some serious coin during these months! However, if you plan it right, it might be cheap enough to be feasible.
The summer will see the most weddings for sure. However, you can use this to your advantage and can get some great deals on accommodations in the winter. For the most part, there really isn't much of a winter here in Hawaii, but you have rainy seasons where the temperature cools off significantly. You can save a lot of money by booking your wedding during the rainy season.
In Honolulu, the season is fairly tame, and if you are booking your ceremony for an indoor venue you'll have nothing to worry about.
"What about soaking up the Sun and getting a tan?" you may ask? Although it's the rainy season, there's still plenty of opportunities to hit the beach and cook yourself. The temperature hardly gets below the high 70's (24 celsius) and the rain is intermittent, and for the most part very weak.
What should you expect in Hawaii?
Believe it or not, many people from around the world do not know that Hawaii is the 50th State of the U.S. (many people also do not know that Hawaii was illegally annexed when the US was building its empire). Regardless, if you speak english you will do perfectly fine. However, since Hawaii is a multicultural landscape, you will hear many people speak Hawaiian, Pidgin English, Japanese, Korean, Chinese, Portuguese, Spanish, among others. So, if English is a second language, most retailers have staff who can speak Japanese, Korean, or Chinese.
In addition, if you are coming from the US mainland, expect to hear some difference in words when you go shopping. The first western colonizers of the islands were British and you will hear the slight difference. For instance, when you go shopping you'll be putting your groceries in a "buggy" not a "shopping cart." If you are coming from Australia, New Zealand, or Canada (or anywhere else for that matter), you will find a ton of currency exchanges in the downtown area. There are a few of them at Ala Moana mall.
On the topic of money, be prepared to nickled and dimed if you plan to come during the peak season. If you are staying at a resort, be prepared to charged for everything and discover that all the cheap local places are too far away to find on foot (a true tourist trap). But if you have the money, it's incredibly convenient since travelling around the island is a huge pain! Traffic in Honolulu is some of the worst in the US.
Above all else, take everything I say here with a grain of salt. I say, wedding in the winter, or honeymoon in the summer because of the conveniences and savings. But of I also suggest weighing everything I've written against the Hawaii Visitors Convention Bureau (www.gohawaii.com).
Good luck! Have fun! And Aloha!