Will my teens be able to swim in the ocean in December? What is the Jelly fish situation? I have not seen it mentioned much. They freak me out. We are going to Sydney, The Whit Sundays, Townsville and Cairns. Please advise. Many Thanks.

There are none of the above in Sydney so swimming in the ocean is fine. As for The Whitsundays, Townsville and Cairns all precautions are taken in the area but I will leave the explanations by the locals from this board. All areas in the Tropics around the World have the same problem with stingers of all sorts so the Australian tropics are no different except that we let people know and take every precaution to stop any problems.

As the Box Jelly fish breed in creeks it is the near shore waters which are dangerous for the them and yes you will be there right in their peak season. So swimming in the ocean near the coast at those three northern locations should only be done in stinger nets.

Out on the reefs it is a different matter but always listen to the safety advisories. The stinger suits which are available for hire will also protect from other species of marine stingers and sunburn.

We went snorkelling on the GBR from Port Douglas in December and had to wear stinger suits.

What is the stingerfish situation in the Port Douglas reef areas in the third week in March generally?

About the same as any other week in March, but as Alan has pointed out they breed in mainland coastal creeks, not out on the reef - just be guided by crew, full body lycra stinger suits are available on all reef boats. Four Mile beach at Port Douglas has a stinger proof net, but once again, if stingers are about, the lifesavers will close the entire beach, stinger net area included.

"Same as any other week in March". That does not mean anything to a tourist from the US. The bottom line is that we will be guided by local knowledgeable guides.

I'm sorry, but I don't think anyone can tell what the marine stinger prediction is for a particular week in March, although March is still within the "official" stinger season which can continue to May and even June in the more northern tropical waters.
Weather conditions on the day have an influence, see above post.