The weather in July 2025 was dominated by the
southwest monsoon, which prevailed over the Andaman Sea, Thailand and the Gulf
of Thailand, with moderate to rather strong at times. Additionally, the monsoon
trough lay across Myanmar and northern Laos and, it shifted southward to lie
over the upper northern region of Thailand and northern Laos at times.
Moreover, a low-pressure cell covered upper Vietnam for most of the month and
over upper Laos for few days. Moreover, at the end of the month, the tropical storm
“WIPHA, (2506)” made landfall at upper Vietnam on 22 July and gradually
weakened into an active low-pressure cell as it moved over upper Laos and the
upper northern region of Thailand, as well as northern Myanmar. These resulted
in plentiful rainfall over upper Thailand, particularly in the northern and
upper northeastern regions. Heavy to very heavy rainfall occurred frequently,
causing flooding in many areas, and landslides in some places, especially in
Chiang Rai, Nan, and Phayao provinces, which experienced intense rainfall and
severe flooding. The maximum daily rainfall and monthly total rainfall recorded
in these areas exceeded previously highest recorded of July. In the southern
region, the moderate to rather strong southwest monsoon brought plentiful
rainfall, especially along the western coast, in the beginning and the middle
of the month. However, at the end of the month, rainfall was obviously
decreased due to the influence of a high-pressure system from the Southern Hemisphere
that extended to cover the Andaman Sea and southern Thailand. Monthly rainfall
was above normal in the northern part 84.6 mm (45%), northeastern part 3.1 mm (1%)
and central part 2.2 mm (1%). It was inversely below normal in the eastern part
43.6 mm (15%), southern part (east coast) 49.3 (41%) and southern part (west
coast) 138.0 mm (39%). The average total rainfall over Thailand in
July was 1% lower than normal. Overall, the average temperature over Thailand
was 0.3 ˚C higher than normal. The details are as follows.
Announcement Date 31 July 2025 11:17
