Thailand Weather in January

January is the cool season in Thailand, characterized by predominantly hot but not scorching and relatively dry weather nationwide. However, notable climatic variations persist across different regions: the north experiences a significant diurnal temperature variation, with a slight chill in the early morning and evening; the central region enjoys a mild and pleasant climate, making people feel comfortable; the south features early-summer-like warmth, which remains moderate and non-stifling.

Temperature

Due to the different terrains and latitudes, the temperatures in the northern, central and southern parts of Thailand in January are different.

Owing to the mountainous and plateau terrain, northern Thailand experiences the lowest temperatures in the country during January. Chiang Mai serves as a representative example: nighttime lows range from 14 - 18 degrees Celsius (57 - 64 degrees Fahrenheit); wearing only short sleeves might make you shiver a little. However, during the midday, temperatures soar sharply to 28 - 32℃ (82 - 90℉), accompanied by mild sunshine, creating favorable conditions for outdoor activities such as exploring Old City and visiting local markets.

The central region is located on the Chao Phraya River Plain influenced by the monsoon, so the temperature here in January is much more stable. For instance, in Bangkok, the daytime highs are 30 - 34℃ (86 - 93℉); if you apply sufficient sun protection, you will only sweat slightly when going out. At night, the temperature is 21 - 24℃ (70 - 75℉), just like a natural air-conditioned room, which is comfortable and pleasant.

The southern region borders the Gulf of Thailand and lies at a lower latitude, resulting in higher temperatures in January compared to the other regions. For instance, in Phuket, daytime temperatures range from 33 to 36℃ (91 - 95℉), while nighttime temperatures typically fall between 25 and 27℃ (77 - 81℉). Nevertheless, the prevailing sea breeze mitigates the heat, creating a friendly climate for beachside strolls.

Precipitation

Average precipitation: 20 mm from 3 rainy days

Under the influence of the northeast monsoon and insufficient moisture transport, rainfall across Thailand is scarce in January. In Chiang Mai, for instance, there is only one rainy day in the month on average, with cumulative precipitation less than 10 mm. Even when there are occasional showers, they were fleeting: you might get sprinkled with a few drops while wandering the ancient city, yet the rain stops before you can even find a shelter, leaving the air feeling fresher and more pleasant.

However, the southern region is affected by the moisture from the Gulf of Thailand, resulting in a slightly higher rainfall. For example, in Phuket, there are about 4 rainy days with a total rainfall of 23 mm in January. But there is no need to worry at all, for these brief and sporadic showers are generally negligible and are unlikely to interfere with travel plans.