BANGKOK, THAILAND – Cooler air masses were expected to return to much of Thailand in early February after a brief warming, according to a seven-day forecast by the Thai Meteorological Department.
Warming trend with morning fog
Meteorologists reported rising temperatures in upper Thailand and the upper South through 31 January, while mornings in the far North and Northeast remained cool to cold with widespread fog. The agency said this followed a weakening high-pressure system over upper Thailand and the South China Sea, which had eased an earlier cold spell.
New surge of cool air expected on 1 February
From 1 February, the Thai Meteorological Department (TMD) forecast a marked temperature drop in upper Thailand, with the Northeast expected to see partly strong winds. The change was attributed to a new, moderately strong high-pressure area from China extending over upper Thailand and the South China Sea, bringing back cooler conditions.
Health risks from fine dust and haze
The agency explicitly warned residents in upper Thailand of health risks from increasing fine dust and haze between 26 and 31 January, when weak airflows and poor ventilation led to a stronger build-up of dust particles and smoke. It highlighted an elevated risk for people with respiratory diseases and noted that weak winds and persistent inversions were favouring the accumulation of particles.
Noticeably cooler in the North
In the North, conditions remained cool to cold with morning fog, and mountainous areas reported cold to very cold nights with isolated frost at lows between 2 and 12 degrees Celsius. Between 26 and 31 January, lowland temperatures rose slightly by 1–3 degrees, to 14–23 degrees at night and 29–34 degrees during the day, while mountain areas stayed fresher at 8–14 degrees.
Forecast temperature drop and stronger winds
For 1 February, the TMD expected the North to turn cool to cold and windier again, with temperatures forecast to fall by 1–3 degrees to 13–22 degrees minimum and 28–33 degrees maximum. In highland areas, readings of 6–13 degrees were anticipated, while northeasterly winds were expected to freshen to 10–30 km/h.
Conditions in central, eastern and southern regions
In the central and eastern regions, the TMD reported cool weather with morning fog and a slight temperature increase of 1–3 degrees. Off the eastern coast, wave heights remained below 1 metre near shore and 1–2 metres further out at sea.
Thunderstorms and waves in the South
In the South, a moderate northeast monsoon over the Gulf of Thailand and the Andaman Sea brought isolated thunderstorms, with storms occurring in 10–20 percent of areas along the eastern coast amid still-cool mornings. In the lower Gulf, waves reached 1–2 metres, while in the upper Gulf and nearshore Andaman Sea they were around 1 metre, rising above 2 metres in thunderstorm zones.
Maritime caution and outlook for Bangkok
All vessels were urged to exercise particular caution, avoid stormy areas associated with thunderstorms and navigate carefully. For Bangkok and surrounding areas, the TMD reported cool mornings with fog and a temperature rise of 1–3 degrees during the period.
Dynamic pattern at the turn of the month
According to the forecast, the weather pattern remained dynamic, with milder days giving way to a noticeable return of cooler air masses around the turn of the month, especially in the North and Northeast of the country.
“The weather situation will remain changeable, with a brief warming, increased fine dust accumulation, and then a renewed cooling with stronger winds at the beginning of February.”
said the Thai Meteorological Department, in its seven-day outlook.