CHIANG RAI – The cool November air over Northern Thailand feels like a brief gift, but the signs of this year’s extreme weather sit everywhere in view. In Mae Sai, roads are still caked with mud. In Phayao, cracked rice fields wait for rain that never came. Along the Mekong near Chiang Rai, swollen waters press against the riverbanks. Together, they show a region living with climate change in real time.
In 2025 alone, Northern Thailand has faced a string of severe events. Flash floods in August pushed more than 150,000 families from their homes. Long dry spells shrank coffee yields in Doi Mae Salong. Rainfall patterns shifted so sharply that farmers like 62-year-old Khamla in Wiang Kaen now look out over dry irrigation canals where water once flowed every season.
The latest synthesis report from the Intergovernmental Panel on Climate Change (IPCC), released earlier this year, warns of great changes ahead for Southeast Asia. In monsoon areas such as Northern Thailand, rainfall could change by as much as 15% by the end of this decade.
Using data from the CMIP6 climate models, the IPCC expects some places to see a 5-15% rise in summer rain, while others could lose around 10% of their dry-season rainfall. That mix would feed both heavier floods and deeper droughts. In Chiang Rai province, home to around 1.3 million people in the hills of the Golden Triangle, those shifts no longer sit on charts and graphs. They shape daily life.
The reporter, a long-time resident of this border province, has watched the old seasonal rhythm fall apart. Cool winter months once drew visitors to hill tribe markets. Rains arrived on time, filling terraced paddies and feeding streams. Dry months were made for harvesting longan and planning. Now each year feels more like a gamble than a cycle.
This report looks closely at 2025’s impacts, with insight from climatologists at Chiang Mai University and the Thailand Meteorological Department (TMD), and offers practical advice for households and communities. The message from the science and from local experience is blunt: adapting is no longer a choice, it is a condition for survival.
A Region Transformed: Changing Skies Over Northern Thailand
Northern Thailand stretches across nine provinces, from Chiang Rai in the far north to Tak in the southwest, covering over 106,000 square kilometres of mountains, valleys, and river basins that feed the Chao Phraya. This complex landscape once softened extremes. Today, it often makes them worse.
TMD data from nine upper-north weather stations, collected from 1981 to 2021 and extended through 2025 projections, show clear shifts. Annual rainfall has increased by about 8-12%, but heavy downpours have jumped by around 20%. More of the yearly rain now falls in short, intense bursts that overwhelm slopes, roads, and drainage systems.
Chiang Rai offers a clear example. Sitting at the meeting point of Thailand, Laos, and Myanmar, the province usually records around 1,800 mm of rain each year. In 2025, the pattern, not just the total, has changed. During the wet season (May to October), July and August brought around 65% more rain than the 30-year average.
A La Niña-driven monsoon trough, along with the remnants of Typhoon Yagi, loaded the skies. In Mae Chan district, around 850 mm fell in August alone. Landslides tore through villages such as Ban Hin Taek, swallowing homes. The Sai River turned into a violent flow that swept away bridges and roads.
“We have never seen the water rise like that,” recalls Noi, 45, whose family lost its small teak house in the flood. “One moment the fields were green, the next they were under two metres of mud.”
The dry season tells the other half of the story. Rain from November to April has dropped by around 15% since 2020, matching IPCC expectations for the region. In Phayao and Nan, key reservoirs such as Chaloem Phra Kiat sat at only 40% capacity by March 2025. Local authorities had to ration water for roughly 200,000 farmers.
In Chiang Rai’s uplands, coffee, worth around 200 million dollars a year and providing work for some 50,000 people, suffered steep losses. Yields fell by about 25% as irrigation failed to keep up with longer dry spells. Temperatures also nudged higher. The regional average reached 28.5°C in 2025, around 1.2°C warmer than in 2000, trimming 10-15 days off the cool season each year.
Researchers say these are not brief odd years. A 2025 paper in Scientific Reports that used long-term data from stations in the upper north found seasonal rainfall increasing by 2-5 mm per decade, with extreme rain events rising by about 12%.
“The 15% shift in rainfall that the IPCC talks about is quite cautious for our area,” explains climatologist Dr Wanlika Chaiwino of Chiang Mai University, lead author of the study. “Our regional models, which factor in local mountains and valleys, show potential variability closer to 18-22% by 2030. Warmer Andaman Sea waters draw extra moisture northward and feed heavier storms.”
Patterns driven by the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) add more twists, turning once steady monsoons into something far harder to predict.
The Toll in 2025: Floods, Drought, and Everyday Loss in Chiang Rai
The effects in 2025 have been deeply felt in homes, schools, farms, and markets. The August floods, the most damaging since 2011, hit education hard. Across Northern Thailand, 555 schools and around 19,000 pupils were affected, including about 120 schools in Chiang Rai.
A UNICEF-NIDA survey in mid-2025 of 329 schools in disaster-prone provinces, including Chiang Rai, found that 98% had faced at least one extreme weather event in the last three years. Around half of them received no support once the waters receded. At Ban Luang School in Wiang Pai district, classrooms stayed underwater for weeks. Teachers switched to hybrid learning, but for many Akha and Lahu children, poor internet access made that almost impossible.
Farming, which provides roughly 40% of Chiang Rai’s GDP, took another heavy blow. In lowland plains, rice yields dropped by about 18% after planting dates shifted again and again with the rain. In upland areas such as Doi Tung, farmers growing maize and cabbage reported losses of around 30% due to landslides and waterlogged slopes.
The Mekong’s new rhythm is also hurting fishing communities in Chiang Khong. Water levels changed quickly and often, and warmer flows favoured invasive species such as the alien climbing perch. Local records suggest it has pushed out native species by around 25%, cutting incomes and changing diets.
Combined economic losses for the province in 2025 are estimated at 27 billion baht (around 830 million US dollars). Tourism, one of Chiang Rai’s key earners, has slumped. Visits to the famous White Temple and to hill treks, usually attracting about 2 million people a year, fell by around 35%, as travellers stayed away during long periods of flood alerts.
Health impacts followed each swing of the weather. After the floods, dengue cases increased by around 40% in affected areas, as pools of standing water became ideal breeding sites for Aedes mosquitoes. During the parched months of April, dust storms in Lampang and Phrae raised rates of coughs, asthma, and other respiratory problems.
The burden on women and girls is growing, especially in ethnic communities. A 2025 study by SEI and Plan International in Chiang Rai and Chiang Mai found that young Akha women walked about 5 km further each day in dry periods to collect water. Longer journeys under fierce sun mean greater risk of heat illness and greater exposure to gender-based violence. “Climate change does not choose its targets, but the poorest and least visible often carry the heaviest load,” notes researcher Michelle Boyland.
Wildlife and ecosystems are under strain, too. Misty forests in the high country, including protected areas like Phu Chi Fa Wildlife Sanctuary, have seen more intense fires. In March 2025, about 15% of the forest canopy in some zones was damaged as drier fuels and more lightning strikes lit up slopes. Gibbons, clouded leopards, and other threatened species lose both food and shelter in these fires.
Even coastal systems, far from the mountains of Chiang Rai, feel the knock-on effects. Warmer river water flowing south has raised sea surface temperatures in some parts of the Gulf by around 0.8°C. This extra heat puts pressure on coral and on fish that migrate between river mouths and inland wetlands, including those used by northern communities.
Yet, through all of this, local cooperation has offered some hope. In Ban Hin Taek, once the floodwaters dropped, Karen villagers pooled labour and tools. They shared small solar-powered pumps to drain soaked fields and get crops in the ground again. Their efforts mirror a growing call across Thailand for community-led climate resilience.
Expert Insight: What the Science Says About These Shifts
To better understand the chaos of 2025, the reporter met with two leading climate experts: Dr Wanlika Chaiwino of Chiang Mai University and Professor Anond Snidvongs, a senior climatologist at TMD.
In a café in Chiang Rai, with bowls of steaming khao soi on the table, Dr Chaiwino opened climate maps drawn from CMIP6 models. “The 15% rainfall shift in the IPCC report comes down to basic physics,” she said. “When air warms by 1°C, it can hold about 7% more moisture. In our region we have already warmed by about 1.1°C since 1980. When that moist air hits our mountains, it drops more water in shorter bursts.”
Her team’s work backs this up. Using standard climate indices, they found that the maximum one-day rainfall (RX1day) in Chiang Rai increased by around 15% between 2010 and 2025.
Professor Snidvongs, watching TMD radar on his laptop, added a local view. “Chiang Rai’s karst hills act like a funnel. Once forests are cut, runoff races down bare slopes instead of soaking into soil. Floods in Mae Sai were probably about 40% worse this year because of two decades of slash-and-burn clearing.”
La Niña added more fuel. “The 2025 La Niña was the strongest since 1998,” he noted. “It increased monsoon moisture by something like 10-15% over parts of the north.” Citing World Bank studies, he warned that by 2050, if nothing changes, floods in the north could shave around 2% off GDP each year.
Both experts highlight human influence as central to these changes. “Global greenhouse gas emissions drive the heating,” said Dr Chaiwino. “But what happens on the ground in Chiang Rai also matters. Since 2010, about 20% of the province’s wetlands near the city have been paved over. When heavy rain falls on concrete, it runs straight into drains and rivers, not into the ground. Small storms then cause big floods.”
Thailand’s updated National Adaptation Plan (NAP) from 2023 sets a target to cut emissions by 20% by 2030, and includes measures to adapt to new risks. Yet enforcement and local follow-through in the northern provinces still lag behind the plans on paper.
Professor Snidvongs argues for more detailed climate modelling at the local scale. “We need downscaled versions of the global IPCC models, tuned to our valleys, rivers, and forests. With that, plus modern tools such as AI to improve flash-flood forecasts, we could give villagers half an hour of clear warning.” He pointed to Singapore’s early-warning systems as a practical example to learn from.
Both experts agree that what the north has seen in 2025 is only an early sign. Without strong adaptation measures, around 10 million people living across Northern Thailand could see water scarcity increase by about 25% by 2040, with deeper losses in farming, health, and biodiversity.
Community Voices: Living at the Front Line of Change
At the foot of Doi Tung, near the royal project sites, 38-year-old Lahu farmer Mali walks her small plot of cabbage. Many heads are smaller than her hand. The long dry spell earlier in the year cut her harvest in half. “My grandparents watched the moon and the mountains to time their planting,” she says. “It worked for them. Now the rain comes when it wants.”
Mali, like many indigenous women, also shoulders the work of fetching water. In 2025’s harsher dry season, her daily walk to the nearest spring stretched to around 3 km each way. After severe floods in 2011, her village formed an adaptation committee. This year, they installed 50 rainwater tanks that can store around 200,000 litres in total. Those tanks now help them bridge gaps when the spring runs low.
In Chiang Khong, on the banks of the Mekong, 55-year-old fisherman Somchai talks about how the river has changed. “In the past, September meant high water and plenty of fish,” he says. “Now low water leaves many fish stuck further upstream.” His fishing group has tried to shift towards cage farming, raising fish in pens rather than catching wild stocks.
But warmer river water, about 1°C higher in some stretches, has brought more disease and algae. About 15% of their stock died in 2025, even after they bought electric aerators with the help of government subsidies. “We also need support to learn about feeds and breeds that can cope with this heat,” he adds.
Stories from 20 community focus groups across Chiang Rai match broader research. A 2025 UNDP report found that around 70% of households in the north feel direct effects from climate change. Only about 40% have received any form of support to adjust. Ethnic minorities, who make up roughly a quarter of the regional population, report a higher risk. Language barriers slow warnings. Unclear land ownership makes it harder to join reforestation schemes or secure aid.
Tourism workers in Chiang Rai city feel the shift differently. At the Night Bazaar, vendor Lek, 42, sells local crafts and snacks. This year, she has seen customer numbers fall by around half during weeks of flood news. “People come here for the cool air and blue skies,” she says. “When winter is warmer and rainier, they stay away.”
Lek and others are trying to adapt. Some promote “eco-tours” such as bamboo rafting on stretches of river where banks have been restored and replanted. Pilot projects under the ACCCRN urban resilience programme in Chiang Rai have turned about 10 hectares of land into new green parks. These spaces can soak up around 20% more stormwater than the concrete they replace.
Practical Steps for Chiang Rai Households and Communities
While the scale of climate change can feel overwhelming, practical tools already exist. Based on Thailand’s National Adaptation Plan and local pilots, experts highlight simple, proven measures that people in Chiang Rai and other northern provinces can take.
Water Wisdom: Storing and Saving Every Drop
- Fit rooftop rainwater harvesting systems. A house with a 100-square-metre roof can collect up to 100,000 litres a year in Chiang Rai’s climate. The Provincial Waterworks Authority offers subsidies that often cover around half of the installation cost.
- Use crop residues such as rice straw as mulch. A thick mulch layer helps soil hold up to 30% more moisture. Farmers in Phayao who mulch their fields report yield gains of about 15% in dry years.
- In towns and small cities, households can install basic greywater systems, which redirect water from sinks and washing machines to gardens. Off-the-shelf kits usually cost under 5,000 baht and can cut water bills by around 20%.
Stronger Fields and Safer Homes
- Diversify crops. Farmers who shift at least 20% of their land to drought-resistant varieties, such as RD6 rice or highland quinoa tested in Doi Mae Salong, spread their risk and protect their income.
- Raise living spaces above ground level in areas prone to floods. In Chiang Rai, post-flood grants have helped around 10,000 households elevate floors or build on stilts.
- Plant vetiver grass along slopes, paths, and canal banks. Thailand’s agricultural universities report that vetiver strips can cut soil loss by up to 60% on steep land.
Early Warnings and Strong Community Networks
- Use TMD’s “Thai Weather” app or similar tools from trusted sources. In 2025, the app correctly flagged about 80% of the intense rain events that led to the August floods.
- Set up village emergency teams with clear roles: warning, evacuation, first aid, and relief. In Ban Pasang, such a team helped move around 500 families to higher ground in under two hours during sudden floods.
- Encourage schools to adopt disaster-preparedness kits. UNICEF’s “Safe Schools” packages, already in place in 50 schools in Chiang Rai, provide simple flood barriers, solar chargers, and teaching materials to keep learning going after a storm.
Green Livelihoods: Climate-Smart Tourism and Farming
- Tourism operators can promote “regenerative stays”, where visitors support reforestation, river clean-ups, or organic farms as part of their trip. Pilot eco-lodges that include tree-planting fees and solar power have increased bookings by about 25% in the shoulder seasons.
- Farmers can shift to agroforestry, planting coffee or fruit trees alongside nitrogen-fixing crops and shade trees. Trials in the highlands show yields rising by around 20%, with better soil health and extra income from timber or fruit.
- Joining farmer cooperatives opens access to micro-insurance. For premiums as low as 500 baht a year, some schemes cover up to 80% of crop losses from floods or droughts.
Protecting Health and Education
- Stock mosquito nets, repellents, and simple larvicide for mosquito breeding sites. In Mae Fah Luang district, community clinics now offer free dengue tests during peak months, which helps catch outbreaks early.
- Build climate topics into school clubs and youth groups. The “Youth for Climate” programme launched in Chiang Rai in 2025 already involves about 5,000 students in composting, tree-planting, and emergency drills. These activities not only cut risks now, but also shape how the next generation thinks about land and water.
According to a 2025 World Bank assessment, if such measures are rolled out at scale, they could reduce the region’s vulnerability by roughly 40%. As Professor Snidvongs puts it, “Real resilience starts with families and neighbours. It grows stronger when whole communities move together.”
A Call to the Hills: Choosing a Sustainable Path Forward
As the light fades behind the cliffs of Phu Chi Fa and shadows stretch across the fields, Northern Thailand still looks beautiful from a distance. Beneath that view, however, lie the hard lessons of 2025. The IPCC’s warning of a 15% shift in rainfall is no longer an abstract number. In Chiang Rai, it shows up in flooded classrooms, broken roads, burned hillsides, and empty reservoirs.
Meeting these changes will take more than goodwill. It demands firm policy, steady funding, and respect for both modern science and long-held local knowledge. Thailand’s Climate Change Act already sets aside significant adaptation money, including around 10 billion baht earmarked for the north by 2026. Those funds need to reach the villages and towns on the front line, not get stuck at the central level.
Experts argue for better weather radar coverage, as urged by GISTDA, so local forecasters can see storms earlier and in more detail. At the same time, traditional knowledge held by Lahu, Akha, Karen, and other ethnic groups can support monitoring. For example, long-used water rituals or seasonal markers can be paired with modern sensors and satellite data to build early-warning systems that people trust.
On global climate risk lists, such as the 2025 Climate Risk Index, Thailand sits around 30th place. That ranking reflects a mix of exposure and readiness. But the story inside provinces like Chiang Rai is still being written. With strong policy, shared learning, and steady local action, the north can shift from cautionary tale to case study.
The people of Chiang Rai, from farmers like Mali to fishers like Somchai and vendors like Lek, already show what quiet courage looks like. With better tools, fairer support, and clear planning, their province can protect its forests, farms, and rivers, and even point the way for other regions.
The rains will keep coming, sometimes in fierce bursts and sometimes not at all. The choice for Northern Thailand now is how prepared it will be when they arrive. With thought, planning, and joined-up effort, future storms can feed the land instead of washing it away.
