Will be in Vietnam, Cambodia, Thailand and Hong Kong mid November into mid December. I know what average temps. will be from the weather websites but how about the humidity percentages? If the temp is 70 but it is 90% humidity I know I'll be hot. So, I'm trying to figure out a travel wardrobe that I can fit into a carry-on. Any suggestions. Thanks

Go with 100% cotton and/or linen. Mix and match outfits. Sandals, a good hat or sun umbrella.

Avoid denim, polyester, silks as these do not absorb moisture very well.

Avoid sneakers.

I second Bill's suggestions. Generally light cotton pants that are loose work best for me. Also bring a pair of good walking shoes that breathe in addition to the sandals.

Really great in humidity are the special fabrics made for sports that wick sweat from your body. Coolmax is one of them that I have a lot of and wear every day. I find my coolmax t-shirts to be lighter weight and cooler than my cotton ones...added bonus of never wrinkles in Coolmax. I also have Coolmax pants, but finding ones that didn't scream sports club were tough.

I second KimJapan's suggestion. Sporting goods stores carry lots of clothing for excercize that is far superior to cotton for heat and humidity as they wick the moisture away from you and dry very quickly. In addition to the brand that Kim mentioned, Russell Athletic and The North Face carry tops that are also very good. Also, pants that convert into shorts that are very light weight and dry quickly are also good. The North Face is great for these. I bought about seven pairs of these online and they are the best. They are now part of my travel wardrobe, along with the tops mentioned.

huge humidity....loose fitting cotton and/or linen clothing...comfortable shoes...slacks/capris...some sort of a lite weight wrap to guard against fierce a/c in some places...we take one long sleeve shirt to protect from the sun....fast drying bathing suit...cotton undies and bras...

Humidity everywhere but Hong Kong and Hanoi will generally be between 75-80% in most places, which is not too bad as things go in Asia, you are going at a good time of year (except you will get some rain in Vietnam, esp if you are going to Hue where it can bucket down). Hong Kong will be the exception where the humidity is the lowest all year, it will be at or below 70%. Due to the very mild temps and low humidity, you will find locals in Hong Kong generally not wearing shorts at all, we will be in long pants, sweaters, shawls, and even the occasional jacket or coat (it is winter after all); it may or may not concern you to stand out in shorts, T-shirts, etc. It will be cool in the evenings, esp. towards the middle to end of December. As most homes, offices and shops do not have heat, to keep air circulating, the air conditioning is generally left on which makes places freezing, so do at least have a sweater, esp. for public transport and restaurants.

I think you will find Hanoi to be quite similar to Hong Kong except for the air conditioning. I have not been there since about 1990 when there was not any air conditioning at all to speak of, not sure how things have changed since then.

Why would you want to only limit yourself to carry-on baggage? It is so easy to get around Asia between public transport like the Airport Express in Hong Kong where you can roll your luggage right onto the train, cheap porters, and fairly rapid baggage service at airports, I don't see the need to lug a carry on out and back to the plane and struggle it up into an overhead which is already crowded with other people's stuff. This also means you won't be able to buy any gifts or souvenirs. Not sure I understand the logic of a carry-on to Asia, esp when you will have temperature differences to contend with which means you need to bring more clothing.

Totally agree with Laurieco and KimJapan! Those "dry-fit" clothes are the BEST to wear when it's hot/humid. That's all I wear when it's hot! Quite a few companies make them now including Nike, Adidas, Russell, etc. I'm not sure where you're at, but you can find them at any sporting goods store or Macy's or Robinsons May.