While on the backpacker trail it's easy to get lulled into a false sense of bikinis-are-appropriate-everywhere. But do bear something in mind: Bangkok is not a beach town and that soupy khlong is not the sea. Despite the insufferable humidity, Bangkokians are quite chic and they appreciate when tourists do what they can to observe local etiquette and culture. Dressing for Bangkok can be tricky, but if you take a moment to figure out what attire is best you will save yourself trouble once you’re here.
A few things to keep in mind while packing; practicality, convenience and respect for culture. We’ll start with the first point, practicality. It’s hot, really hot. Unless you are amphibious you will do all kinds of sweating. Fabrics and items that are excellent for keeping you cool? Cotton. Linen. Undershirts. Hats. Things that could add to the misery? Tight jeans. Silk. Pleather. Wear lightweight linen, breathable fabrics and anything that won’t be drenched after a day in the heat. Comfortable and protective walking shoes are also highly recommended as things like the sidewalk are oftentimes shoddy. On the other hand, many Thais miraculously pull off those tight jeans without a glimmer of sweat.
For the sake of convenience, keep in mind that as soon as you go inside it will be highly air-conditioned. We’ve taken to always carrying around an extra sweater or wrap in order to be prepared for the Arctic temperatures that can occur indoors. As Bangkok is a tropical climate, you should also be highly prepared for rain. Rainy season officially lasts from June until October but can encroach on the surrounding months as well. During those months it will very probably rain at least once a day, and not a friendly drizzle, but a massive tropical deluge that's usually finished within 20 minutes. Having an umbrella, rain jacket or poncho in your bag could be a lifesaver.
Now, on to culture. Thai people are very well-groomed and respect people who are equally well-groomed. Walking the streets shirtless, or entering a government building without shoes on (you’d be surprised) won’t go over well with the locals. Bangkok is not nearly as conservative as Thailand’s rural areas and rules like “you must always cover your shoulders” don’t really apply here. That said, there is a bit of a double-standard among what is acceptable for Thai people (girls especially) to wear and what is acceptable for foreigners to wear. While a Thai girl might get away with tiny shorts and a tank top, a foreigner in the same outfit will be a bit judged.
In addition, many sights, such as Wat Phra Kaew, have strict dress codes. These codes are enforced and you will not be allowed in unless you abide. Shorts are not allowed, shoulders must be covered by some sort of sleeve, and skirts or longer pants must reach nearly all the way to the ankle. Loaner clothes are available at some locations but save yourself the hassle and the threat of a stranger’s lingering B.O. and dress the part.
Our best advice: pack and dress like you will be dressing for summer in the biggest city in your home country. Be mindful of rainy season and always respect the dress codes at temples and other sights. Bangkok is urban, modern and chic. Wear those sundresses and T-shirts and save the bikinis and the bare feet for the beach.