January to March
Peak Season in Thailand
The most popular and therefore the most expensive months to visit Thailand. Humidity is at its lowest for the year and temperatures are slightly lower than normal averaging around 32° from Bangkok southwards. In the north the temperature can drop much lower overnight but during daylight hot sunny days are the norm.
If you wish to go there at this time of year then booking your accommodation and flights at least three months ahead is advisable to be sure you get the lowest air fares and widest choice of rooms. In the most popular destinations such as Phuket its common for the best hotels to be fully booked several months in advance. If you do leave it to the last minute then you can usually still find somewhere decent to stay but it is more difficult and choice can be limited.
January being the peak-month of the year means hotels often charge more than double the rates they do at other times though better value is possible in February and more so in March . The other downside for some people will be the crowded streets, nightlife venues and the increased traffic which in some places makes simple things like crossing a road quite a chore.
The Month of Songkran
The last month before the rainy season starts and often the hottest month of the year. Its also the month of "Songkran" festivals where thai citizens celebrate their new year by enthusiastically dousing each other (and tourists) with cold water.
There is nothing quite like this anywhere else in the world and, as it attracts large numbers of tourists, expect big crowds and increased prices.
For most visitors it's a time of incredible fun but if you are not prepared to take part then be prepared to stay in your hotel room all day as you will not get far along the street before you are completely soaked. You have been warned!
May to August
Low Season Months
These are usually the more pleasant months of the rainy season. The humidity will creep up, the temperature will stabilise at around 35° C. and rain will be a freqent event. However, a common pattern can be a mixed cloudy /sunny day with an intense rain storm that lasts for a couple of hours in the late afternoon so depending on your luck its still possible to get a good suntan.
With the high season crowds absent this can be a wonderfully relaxing time to be there. Bargains abound everywhere from hotels offering special deals to rock bottom prices in the shopping markets.
The rainy months have high average rainfall but its still possible to strike many lovely sunny days and with even the most popular Thai hotels
offering sometimes more than 50% disacount this time of year is well worth considering for those wishing to keep costs down.
September and October
Low Season Months
These are the wettest and most humid months of the year.
Though the chances of major rain storms is high throughout the country there is still a good chance of fine weather periods as well though luck will be needed.
These are generally the lowest months for tourist numbers so usually they are the months to get the biggest discounts on both flights and hotels which can mean paying around half as much for your Thailand trip as it would cost in the high season.
November and December
Start of the High Season
The start of the high season. The rains should clear up and the humidity level reduce but it can't be guaranteed to work out that way so an element of luck applies especially in the south during November.
Still it's a pretty safe bet that you will get good patches of sunshine and calm clear days. Tourism numbers will increase but are still way below January and February.
These months can offer the best of both worlds with a very pleasant climate, moderate numbers of tourists and good prices.