May 2025, hot weather persisted in
upper Thailand during the beginning of the month, with very hot in some areas
of the northern region. After that, from the middle of the month onwards, rainfall
increased in both amounts and distribution across most regions due to the influence
of the southwest monsoon prevailing over the Andaman Sea and Thailand. These conditions
resulted in continuous rainfall across Thailand, indicating the beginning of
the rainy season on May 15. Additionally, the high-pressure area from China
covered Vietnam and the South China Sea in the middle of the month, causing
southeasterly and southerly winds to dominate upper Thailand. Moreover, the
monsoon trough lay across upper Thailand and shifted over
the upper southern region, with the easterly wave pass through the Gulf of
Thailand, southern region and the Andaman Sea for a few days. These conditions
caused widespread rain across Thailand, with intermittent heavy to very heavy
rainfall, inducing flooding in several areas and flash flood in some places. Overall,
the average rainfall across Thailand this month was 52% higher than normal, with
some stations setting new records of the highest daily and monthly rainfall
totals. The monthly rainfall exceeded normal rainfall in all regions i.e.
northern region 89.7 mm (52%), northeastern region 88.7 mm (47%), central region
114.9 mm (69%), eastern region 119.3 mm (58%), southern region (east coast) region
44.8 mm (34%) and southern region (west coast) 196.1 mm (56%). For more details were as follow.
Announcement Date 31 May 2025 16:44