Thai Meteorological Department Outlines Criteria for Winter Season Transition
The Thai Meteorological Department has clarified the three specific conditions required to officially declare the start of the winter season in Thailand.
As Thailand transitions from the rainy season to winter, the Thai Meteorological Department (TMD) has issued guidance to clarify that cooler morning temperatures alone do not signify the official start of the winter season. According to Khaosod Online, the TMD monitors three specific meteorological factors to determine the onset of winter, which typically occurs between mid-October and mid-February.
The three criteria are:
- Minimum daily temperatures must consistently fall below 23°C.
- Prevailing winds must shift to a northeasterly or easterly direction across the country.
- Rainfall distribution across upper Thailand must show a continuous and significant decrease.
For residents and travelers, this distinction is important as it helps manage expectations regarding weather patterns. While many areas are currently experiencing cooler mornings, the official winter season has not yet been declared. The TMD advises the public to remain attentive to official updates to confirm when these conditions are met. As of October 14, 2026, the department has not yet issued a formal announcement regarding the exact start date for the 2026 winter season. Travelers planning trips to northern or mountainous regions should monitor local forecasts, as conditions can change rapidly during this transitional period.
