When to visit Thailand
Inland Thailand has a tropical, humid climate for most of the year. The area north of Bangkok has three seasons whilst the southern peninsular region has only two.
In the north the weather is mostly dry between November and May, though from March to May sees a sharp rise in temperatures as the cooling breezes of the northeast monsoon subside. May to November is dominated by the southwest monsoon, when rainfall is heaviest.
The south is more definitively split between wet and dry seasons. On the west coast the southwest monsoon brings rain and heavy storms from April to October, while on the east coast the heaviest rains fall from September to December. The south gets by far the most rain at around 2,400 mm every year, compared with 1,400 mm in the central and northern regions.
Generally the best time to visit Thailand is the cool season from November to February when temperature ranges from 18°C to 32°C in Bangkok, while in the north and northeast daytime temperatures can be as low as 8°C to 12°C and nights can be chilly, sometimes dropping below freezing at high altitudes.
In the hot and dry summer season from March to June temperatures in Bangkok average around 34°C, but can often reach 40°C with oppressive humidity levels of 75%. April is the hottest month throughout the country. In the monsoon season from July to October there is extensive flooding. Humidity hovers around 90%, and temperatures average around 29°C in a wet and rainy Bangkok.