Bangkok: Thailand enters the rainy season tomorrow, bringing concerns about decreased rainfall due to El Ni±o. The Meteorological Department is set to officially declare the start of the rainy season, cautioning that rainfall this year will be 10% less than normal. Farmers are advised to prepare for a dry spell expected at the end of June. Additionally, vigilance is advised towards the end of the rainy season due to the potential for tropical cyclones and heavy rainfall in certain areas.
According to Thai News Agency, the rainy season in Thailand will officially commence on May 15, 2026, as all meteorological conditions have been met. These include widespread rainfall and prevailing southwest monsoon winds across the country. Northern Thailand's rainy season is anticipated to conclude in mid-October, while the eastern coast of southern Thailand is expected to experience ongoing rainfall until January of the following year. The Meteorological Department predicts that the total rainfall nationwide will be approximately 10% below normal levels due to a weak El Ni±o phenomenon likely to persist until the year's end, potentially leading to slightly higher temperatures than usual.
Particular attention is required during the dry spell from the end of June to early July. Farmers, especially in non-irrigated regions, are advised to plan their planting schedules carefully. From August to October, the forecast indicates a return of heavy rainfall, with the possibility of 1-2 tropical cyclones affecting Thailand. This raises concerns about flash floods and landslides in the North, Northeast, East, and South. However, between May 14-18, heavy to very heavy rainfall is expected in many areas due to a low-pressure system in the Bay of Bengal. The Andaman Sea will see waves reaching 2-3 meters high, prompting caution among sailors. The public is advised to stay informed through announcements from the Meteorological Department.