Thailand is waking up with a brisk reminder that the calendar is turning: a strong high-pressure system sweeping down from China has ushered in a cold snap, whipping up gusty winds, dropping temperatures and stirring stormy seas across large swaths of the country. The Meteorological Department (TMD) says the chill is most pronounced in the north and northeast, with parts of the south also feeling the sting as the northeast monsoon strengthens over the Gulf of Thailand and the upper Andaman Sea.
What’s driving this chilly interlude?
A dominant high-pressure area over upper Thailand — essentially a cool air dam rolling in from China — is the main culprit. It’s packing dry, cool air and brisk northeasterly winds that are dragging temperatures down, especially in the pre-dawn hours. At the same time, a low-pressure pocket over the lower Gulf is turbocharging the northeast monsoon, producing thundershowers that target southern provinces and roughening conditions at sea.
Who’s feeling it — and how cold will it get?
The TMD’s 24-hour forecast (6am today, November 20 to 6am tomorrow, November 21) breaks the country down into clear, weather-savvy chunks:
- Northern Thailand: Night and early-morning lows mostly between 14–21°C, rising to 23–29°C by afternoon. Mountain districts will be the coldest, with temperatures plunging to between 3–11°C. Expect northeast winds at 10–25 km/hr and a definite need for jackets at dawn.
- Northeast (Isan): Lows of 15–18°C and daytime highs around 26–29°C. Highland pockets will dip to 6–12°C. Winds are stronger here — 15–40 km/hr — so it’ll feel cooler than the thermometer suggests.
- Central Thailand: A cool start for the plain around Bangkok with minima of 19–21°C and daytime highs of 26–29°C. Northeasterly winds of 10–35 km/hr will keep things blustery.
- East: Morning coolness (19–22°C) followed by highs of 28–30°C. Winds will push 20–40 km/hr, and the sea will be rough — expect choppy waters close to shore and even rougher conditions further out.
- Southern coasts — Gulf side: Heavy to very heavy rainfall is likely in provinces such as Surat Thani, Songkhla and Narathiwat. Nighttime lows will be 20–24°C with daytime highs of 27–29°C. Winds around 20–40 km/hr and wave heights reaching 2–3 metres — over 3 metres in stormy patches — mean small boats should stay ashore.
- West coast (Ranong to Satun): Expect heavy rains here too. Minimums of 23–24°C and maximums of 27–31°C. Northeasterly winds blow at 20–40 km/hr in the north, easing slightly to 20–35 km/hr further south. Offshore waves are forecast at 2–3 metres, swelling beyond 3 metres in rough areas.
- Bangkok: A cool morning around 20–22°C will give way to a warmer afternoon of 29–31°C, with winds steady at 10–30 km/hr — pleasant daytime temperatures but crisp starts.
Practical tips — stay warm, stay safe
The TMD is urging residents in cooler regions to layer up and look after vulnerable people: babies, the elderly and those with chronic illnesses. Farmers should take precautions to protect sensitive crops — coverings, irrigation adjustments and careful monitoring can limit frost-like damage in highland zones.
There’s a cautionary flip side to the dry, windy weather up north: an increased fire risk. Dry air and gusts make accidental fires more likely, so avoid open burning and be cautious with any heat sources. In the south, the message is different but equally urgent: small boats should avoid heading out while waves reach 2–3 metres or higher, and people living in coastal or low-lying areas should keep an eye on local rainfall alerts.
Why this matters — and what to watch next
Weather systems like this are seasonal but can still disrupt daily life — from ruffling travel plans to stressing crops and fishing livelihoods. If you live or travel in Thailand right now, tune in to the TMD and local authorities for updated warnings and advisories. Pay special attention to marine weather bulletins if you’re planning to head out on the water, and stock up on warm clothing if you’re heading north to enjoy the crisp mountain air.
In short: layer up for the mornings, respect the sea’s temper, protect vulnerable crops and keep an ear on official updates. Thailand’s weather is flexing its seasonal muscles — a dramatic, occasionally moody display that will pass, but not without reminding everyone to be prepared.
For ongoing updates, check the TMD’s latest forecasts and local advisories — especially if you live in the highlands, the Gulf-side south or coastal western provinces. Stay warm, stay dry, and if you’re out and about in Bangkok, enjoy the refreshingly cool start to the day.
Cold mornings in Bangkok are refreshing but the warnings for the south sound serious, someone needs to tell the tourists to avoid boats.
As a small-scale fisherman’s son I’m worried — those 3m waves will ruin livelihoods and the government always reacts too late.
You can’t just tell tourists to behave; it’s the tour operators and authorities who should cancel trips when advisories are out.
I agree with Nadia, but local guides sometimes ignore bulletins because money talks, and that hypocrisy needs calling out.
Fishermen in Surat Thani and Songkhla, please stay ashore — my cousin’s fishing boat got swamped last year when they ignored similar forecasts.
We know the risks but bills don’t wait for the weather; sometimes staying ashore means losing days of income and feed for families.
That’s exactly why the state must provide emergency pay for fishermen during dangerous conditions rather than blaming them for going out.
I wish there was a reliable fund, Maya, because the moral pressure on fishermen to risk seas is real and deadly.
This cold snap fits expected seasonal variability, but stronger monsoon surges interacting with high-pressure systems could become more erratic with climate change.
Climate change? Every year we get cold or hot; blaming everything on climate is getting old and political.
Tony, it’s not politics; the frequency and intensity of such interactions are measurable, and dismissing science hinders preparation.
As a tourist I’m thrilled by cooler mornings in the north, but if weather gets unpredictable I’d rather know sooner about cancellations.
Fine, but don’t use one cold snap to sell a century-long narrative; people are tired of fearmongering.
Farmers in the highlands, protect your crops — covering and adjusting irrigation helped save my peppers last winter.
Many smallholders can’t afford covers or extra irrigation, Chai; there’s a socioeconomic divide in who can adapt to these snaps.
True, agriguy, but community co-ops and local extension services can mobilize low-cost protection if they actually show up.
Elderly neighbors often feel the cold more — check on older people and make sure heaters and blankets are available.
As someone over 70 I appreciate reminders, but heaters are expensive and sometimes dangerous in poorly ventilated homes.
Then community centers should open warm spaces and volunteers should coordinate safe heating solutions for vulnerable folks.
Media loves a dramatic headline; ‘cold snap’ sells clicks but mornings are only slightly cooler than usual, stop panicking people.
But Larry, headlines help people take warnings seriously and might save lives when seas are rough or fires could spread.
Sam, there’s a line between informing and exaggerating; consistent over-warning desensitizes the public to real danger.
If people get desensitized, it’s because coverage is inconsistent; be clear and factual instead of melodramatic.
Marine warnings are underplayed; local boat operators need stricter enforcement and fines for ignoring advisories.
Enforcement helps, but many operators are from poor communities — fines could worsen poverty unless paired with support.
Exactly, Preecha. Punishing us for trying to feed families is just cruel; offer subsidies or safe mooring instead.
I meant enforcement plus alternative relief, not blind fines; safety must be prioritized but compassion is essential too.
This is a reminder that climate resilience investment is urgent, especially for coastal communities facing storm surge and rough seas.
Agreed, Maya — targeted investments in early warning systems and livelihood diversification reduce both immediate and long-term vulnerability.
Thanks, Emiko — and let’s pressure policymakers to fund those systems now before another disaster exposes gaps.
Love the cool mornings in Chiang Mai, but are there reliable public advisories in English for tourists? I don’t want to be stranded.
Some agencies post English updates but it’s patchy; best to follow TMD official channels and local tour operators with good reputations.
Why does wind make things feel colder? Is 14°C really that cold for people used to hot weather?
Wind increases heat loss from the body, Sam; for people acclimated to tropical temps even 14°C can feel quite chilly.
Thanks, that helps; I’ll tell my mom to bring extra sweaters for my little brother before school.
Heavy rain in the south will trigger crop diseases; plantations need preemptive fungicide checks and drainage ready.
Chemical use must be balanced with environmental impact; integrated pest management and drainage fixes are cheaper long-term.
I agree agriguy, but sometimes quick fungicide application prevents total loss, though I try to minimize chemicals when possible.
I love the cold mornings in the mountains, makes the coffee taste better and market visitors happier, no drama here.