Thailand has three seasons basically:
November-February = Hot.
March -May = Hot and humid.
June-October = Hot and Wet (rain season)
Whenever you go it will be hot. Be sure to pack light weight cotton shirts, shorts and sandals if you wear them. Thailand can be mostly a casual affair but if you are going to temples or to the palace you need to dress appropriately. Men, no shorts and long sleeves are preferred. Ladies, no shorts, short skirts or halter tops. If you will be in Thailand for a few weeks you'll notice a need for a few showers a day (it can be that hot) Which means going through some clothes. Around every corner is a Thai Laundry which will take care of your clothes for you and at bargain prices. The hotels offer the same service but at much higher rates and usually they take them around the corner to the same shop! You'll also find many markets selling clothes cheaply so don't over pack...save the room for the trinkets you'll be bringing back.
As far as toiletries go you can find everything you need in Thailand cheaply. So, unless you have a favorite you can't live without you can get all your supplies at stores like 7/11, Carefour and or Tesco. No need to add all the extra weight and buy new toiletries for the trip when you can get it there and much cheaper.
Being a hot climate you'll find yourself drinking more water than usual probably. DO NOT drink the tap water. Brushing your teeth and rinsing is fine as well as ice cubes in shops and restaurants. Even the Thais drink bottled water for the most part and it can be had very cheaply, especially the Thai brands.
Food is everywhere and in the tourist areas you can get anything and everything, from Lasagna to Lobster Thermador and all the fast food you could possibly want. Then there is the overwhelming amount of different Thai foods and fruits. If you've come this far for the experience then don't let the Thai food pass you by as it is the best on earth bar none and it is good for you for the most part. Don't be afraid to try different things and don't worry that it might not sit well, you'll never know till you try. Not all Thai food is spicy but you can ask to have dishes prepared less spicy.
Toilets I've covered before in "The Art of Using a Thai Toilet" . If you are mainly in the tourist areas you probably will only run into western style toilets but be prepared for a few things. Number one the bathroom might not have toilet paper and you'll see a hose next to the toilet with a rinser on the end like you have on your kitchen sink. This is used to clean yourself and it works quite well. Might want to carry around some napkins or tissue until you get the lay of the land. You will often see signs when toilet paper is available stating not to flush the paper but instead deposit it in the pail or can provided. Please do as the sign says. Thailand's sewer system can't handle it and it can cause problems quickly. Besides if you use the rinsing hose then the paper is essentially clean anyway.
The outside world is easy to get in touch with as there are internet shops everywhere as well as phone shops to place overseas calls. Most hotels also offer these services but also charge much more for them. If you have a cell phone that uses a sim card you can get it unlocked at many different shops, then you can buy a Thai sim card and call home. Ask the person who unlocked it to set it up for you and the calls home will be cheap! When you get home swap out the sim card to your old one and you're set...and a perk is you're phone will now work on any network.
These are just a few things to consider if your are going on your first trip. Don't sweat the small things because in Thailand you will be able to find most of the things you can find at home, only cheaper.
I'll be adding a series of articles in this area. In the next few rounds of this type of article I'll let you know about getting around town, hotels, markets and nightlife. It would probably be a good idea to touch on the different tourist scams as well...forewarned is forearmed.
