I've been reading that on Oahu approximately 9-10 days after a full moon, that box jelly fish tend to congregate on the leeward side. Does this include Waikiki? Just wondering since it's not quite leeward, but getting close to that area. Also, how many days after they appear do the jellies usually hang around? Thanks.

anyone know?

Don't know the answer, but it has been discussed here previously, suggest searching for jellyfish (jelly fish)under topic of "Hawaii".

At the end of October, we tried to visit Hanauma Bay just beyond Waikiki but it was closed due to Portuguese Man of War jellyfish, we headed north up the coast from there (e.g. Shark's Cove & Turtle Bay) and did not see any jelly fish as described in my recent Trip Report:
http://www.fodors.com/forums/threads...1&tid=34549308

As it turns out the very next day the jellyfish were gone and we snorkeled at Hanauma without incident.

Last year's Link discussing jellyfish:
http://www.fodors.com/forums/threads...1&tid=34468041

Both Waikiki and Ala Moana beaches will have jellyfish during these times. Some of the invasions are worse than others, I think.

I read on the other post of someone saying not to worry about these warnings. That is wrong - the warnings during these invasions are quite valid. You could chance it and perhaps be lucky, but there are often news reports of many, many people being stung right on Waikiki Beach.

Indeed, people do get stung on Waikiki Beach 10 days or so after a full moon. I lived on Oahu for a year and it always made the news!

I'd always heard the windward side was worse for jellyfish. I know my husband and I saw two man-o-wars when we went to Kualoa Beach.

Box jellyfish show up on the south side (Waikiki, Ala moana) based on the moon. Quite a few people ignore the warnings and swim anyway, but not me!

The windward beaches get them on a more regular basis..due to the fact that the wind pushes them that way.

and the moon based invasions usually last 2 to 3 days, depending on the intensity of the invasion. Some times are mild, other times more newsworthy.

Box jelly fish arrive about a week after a full moon. Mostly affecting leeward beaches. Waikiki and Alamoana beaches can get pretty infested. The jelly fish people talk about on the windward sides are actually not jellys but portuguese man o wars. Man o Wars are called that because they have little sails and the ride in on the wind. Thus the windward beaches usually catch the brunt. However, during Kona wind conditions, the windward beaches are totally devoid of man o wars, so thats the best time to go to those beaches.

Another $)02, FYI:
Link below states that Portuguese Man O War is in a different class of jellyfish than the more hazardous Box jellyfish among the various jellyfish classes in the Phylum of Cnidaria.

http://animaldiversity.ummz.umich.ed..._physalis.html

We get these on Kaua`i also -- Po`ipu Beach, mostly. Just had our latest "invasion" early this week.

Mahalo for the update, Auntiemaria, is it the Box jellyfish or Man o War

But will it be enough to keep Kal away from those "secluded" beaches