An intense heat wave This once again places Chile at the center of climate attention in the Southern Cone, with temperatures typical of the harshest summers in southern Europe in the middle of January. While much of the Northern Hemisphere grapples with winter's chill, central and south-central Chile are facing sweltering days that are putting a strain on the... agriculture, public health and emergency services.
The projections of the Chilean Meteorological Directorate (DMC) and various research centers agree on a scenario dominated by High pressure, clear skies, and sustained highs well above normalThis cocktail is contributing not only to heat waves in densely populated cities, but also to a scenario highly conducive to forest fires and productive losses in the countryside.
A warm ridge is driving up temperatures in the central region
The immediate origin of this episode lies in the development of a warm ridge in mid-levels of the atmosphereThis is associated with warm winds that travel through the central valley. According to agroclimatologist Patricio González Colville, from the Center for Research and Transfer in Irrigation and Agroclimatology (Citra) at the University of Talca, this configuration This creates the ideal conditions for a weekend with extreme temperatures.affecting both people and agricultural activity, as well as the risk of forest fires.
Citra models aim for maximum performance among 36 and 38 ºC in agricultural sectors of the Metropolitan Regionespecially in municipalities like El Monte, Buin, Paine, Melipilla, and CuracavÃ. In practice, these are values ​​reminiscent of the More intense heat waves in Spain or the south of France, with the added fact that many Chilean homes are not designed to withstand that much heat.
Further south, in the regions of O'Higgins, Maule and ÑubleVery high readings are also expected. For the most critical part of the episode, urban maximums are projected to be around [number missing]. 36-37 ºCwhile rural agricultural areas could reach nearly 38°C. Subsequently, temperatures would drop slightly, but would remain within a range more typical of an extreme summer than a "normal" season.
In parallel, the DMC has warned of a high temperature event extending from the Coquimbo Region to the BiobÃo RegionTemperatures reached between 30 and 36°C depending on the section and the day. This episode lasted for several consecutive days, which facilitated the fulfillment of the climatological criteria for declaring a heat wave at several reference stations.
Affected regions and heat wave thresholds
The DMC notices clearly define the territorial area affected by this episodeSeven regions in the central zone are among the most exposed: Coquimbo, ValparaÃso, Metropolitan, O'Higgins, Maule, Ñuble, and BiobÃo. In each of these regions, maximum temperatures have been estimated that, in some cases, repeatedly exceed 36°C.
In ValparaÃso RegionFor example, several consecutive days with highs between 34 and 36°C are expected. Metropolitan regionThe forecast points to temperatures between 31 and 34°C in downtown Santiago, but with higher peaks in inland valleys such as Buin or Paine, where the thermometers could approach 35ºC or even exceed it.
In O'Higgins, Maule and Ñuble, the combination of heat and low humidity results in maximum temperatures that, depending on the day, will range between 30 and 37 ° C This applies to both the coastal mountain range and the valley and foothills. The DMC has forecast temperatures for some areas of Maule and Ñuble to reach around 36-38°C, especially over the weekend, thus consolidating several heat waves in a very short period of time.
In downtown Santiago, the Quinta Normal station has already recorded maximum temperatures on the order of 35,2 ° C...linking two consecutive days above the local threshold that defines a heat wave. If the maximum exceeds 33,1 ° C On the third day, the city is officially considered to have crossed a new climatological heat wave, something that has been repeated on several occasions this summer season.
The technical threshold for declaring a heat wave in the Metropolitan Region is around 33,2-33,3 ºC at this time of year. Meteorologists like Andrés Moncada point out that exceeding that mark three consecutive days is enough to trigger the classification. In practice, this has translated into several linked incidents since the beginning of January, which increases heat exhaustion in the population.
Senapred alerts and institutional coordination
Given this scenario, the National Service for Disaster Prevention and Response (Senapred) It has deployed a broad alert and coordination system. In regions such as Maule, Ñuble, and BiobÃo, states of emergency have been declared. regional red alerts for extreme heat, with the aim of mobilizing all available resources and activating special emergency plans.
In the Metropolitan Region and in O'Higgins, the combination of high temperatures, low humidity and wind has also led to Red Alert declarationThis allows for the reinforcement of teams on the ground and the coordination of institutions such as the DMC, the National Forestry Corporation (CONAF), and the Ministry of Health. Other regions along the affected stretch have been placed under yellow alerts, with the possibility of escalating to red depending on how the forecast evolves.
The national director of Senapred, Alicia Cebrián, explained that these alert levels are a response to a continuous technical evaluation of the severity of the eventAuthorities have also stressed the importance of citizens complying with official instructions, especially regarding potential evacuation orders due to forest fires and health recommendations during the hottest hours of the day.
Meanwhile, Senapred has reminded everyone that the SAE emergency messages These alerts are issued only when there is a real and imminent danger to human life. Ignoring these alerts, they emphasize, not only puts those in vulnerable areas at risk, but also the emergency teams that come to rescue them.
The coordination also includes the preventive or temporary closure of national parks and protected areas In those regions where the risk of fires is very high, these decisions are made at the regional level, based on technical reports, and are reviewed periodically as weather conditions change.
Forest fires: a growing risk with extreme heat
The rise in temperatures doesn't come alone. Under this hot and dry pattern, the probability of forest fires skyrockets, especially in the south-central part of the country, where dry vegetation abounds and acts as fuel. perfect fuel for fireResearchers from INIA Quilamapu describe the current scenario as "very bad" from the point of view of fire risk.
The national director of CONAF, Rodrigo Illesca, has detailed that a significant number of active firesSeveral of these fires are currently active, with significant outbreaks in municipalities within the Metropolitan, Ñuble, and La AraucanÃa Regions. One of the most concerning indicators is the so-called "red button," which measures the probability of ignition based on temperature, humidity, and wind, and which currently shows critical values ​​in dozens of municipalities between the Metropolitan Region and BiobÃo.
Projections indicate that, on the hottest days, more than a hundred municipalities could be affected. very high probability of fire starting and spreadingThe combination of heat and low humidity is compounded by increased wind speed, another factor linked to climate change that favors the rapid spread of the fires.
Given this situation, the authorities have reiterated the need to minimize any source of ignitionFrom agricultural work with machinery on dry grass to unauthorized burning, and even recreational activities involving open fires, the message is clear: a single spark is all it takes for the situation to spiral out of control.
Researchers like Raúl Orrego, from INIA Quilamapu, also insist that this succession of heat waves is not an isolated phenomenon, but part of a trend of increasingly longer and more extreme summersIn the Chillán area, for example, several heat waves have been recorded since the end of October, with numerous days above 33°C in just a few months.
Impact on agriculture: water stress and adaptation strategies
The countryside is feeling the full force of this harsh summer. The persistence of very high temperatures for several consecutive days is causing low levels of relative humidity and a sharp increase in evapotranspiration, that is, in water losses from both the soil and the crops.
According to agroclimatology specialists, this extremely dry atmosphere increases water stress levels in plantsThis necessitates more frequent irrigation at specific times to reduce heat stress. Otherwise, there is a risk of significant losses in the yield and quality of fruits and vegetables, which directly impacts the income of farmers and producers.
El animal welfare This is another cause for concern. Authorities and research centers recommend ensuring the availability of fresh water and shaded areas for livestock and other animals at all times. Lack of protection from the heat can lead to production losses and a serious decline in the health of herds.
Experts have also drawn attention to forage management. It is advised Keep the bales in the shade and with a low moisture contentsince the storage of wet material subjected to high temperatures can trigger decomposition processes capable of generating spontaneous fire.
In the area of ​​agriculture, measures such as the following are being promoted: use of shade netting and products that act as "sunblockers" for fruits that have not yet been harvested. Some fruit trees, such as the European hazelnut, show significant leaf damage when extreme heat and intense radiation combine, which ends up affecting photosynthesis and reserves for the following season.
The message from regional agricultural authorities is that, in addition to adapting in the short term with adjusted irrigation and changes in working hours, it is essential plan structural adaptation measures to a climate that, year after year, behaves in a hotter and more changeable way.
Increasingly hot cities and health risks
While rural areas experience their own particular struggle with the heat, cities are not far behind. The phenomenon known as "urban heat island" The heat intensifies in densely built-up areas with little vegetation. Asphalt streets, facades that absorb heat, and buildings that hinder natural ventilation mean that in many cities of the central valley, the heat persists even at night.
This lack of nighttime refreshment reduces the body's ability to recover strength and It increases the risk of heat stroke and cardiovascular problems.This is especially true for the elderly, young children, and those with chronic illnesses. The design of homes, often prioritized over protection from winter cold rather than extreme heat, doesn't help either.
Health professionals have detailed the main warning signs, including silent dehydrationHeatstroke. The most common symptoms include a feeling of intense heat with red, very hot skin, severe headache, dizziness, confusion, slurred speech, nausea or vomiting, and rapid breathing. In severe cases, seizures or loss of consciousness may occur.
In response to these demonstrations, it is recommended Act quickly and seek medical help immediatelyThis is especially important for children, the elderly, or patients with pre-existing conditions. While waiting for help, it's crucial to move the affected person to a cool, shady place, loosen their clothing, offer them water in small sips if they are conscious, and cool their body with damp cloths.
Health and civil protection authorities also emphasize basic preventative measures: Avoid sun exposure during midday hours (approximately between 11:00 and 17:00), hydrate frequently even if you are not thirsty, avoid alcohol and heavy meals, wear light-colored, lightweight clothing and protect yourself with a hat, sunglasses and sunscreen, in addition to paying attention to the UV radiation.
A warming climate: more heat waves and fewer cold waves
Beyond the current episode, data from the Chilean Meteorological Directorate confirms a underlying trend towards an increasingly warmer climateThe year 2025 ended up being classified as exceptionally hot in the country, with a notable rainfall deficit and an increase in the frequency and intensity of heat waves, in contrast to the decrease in episodes of intense cold.
According to figures released by the DMC, throughout 2025, the following were recorded: more than a hundred heat waves in the territoryThe number of heat waves was significantly higher than the previous year, while cold waves decreased considerably. Most of these warm events were concentrated in winter and spring, seasons in which it was traditionally less common to record so many extremely hot days.
In parallel, the Climate Services Office has detected a rainfall deficit in most major cities throughout the country, from Santiago to Valdivia or Punta Arenas, with few exceptions. Less rainfall, drier soils, and a warmer atmosphere, along with the record heat in the oceansThey form a picture that fits with the scenarios described by the scientific community on climate change.
Experts like Raúl Orrego also point out that these extreme heat patterns have been reinforced by the presence of the phenomenon of La niñawhich tends to generate lower temperatures along the coast and very high temperatures in the central valley. Historically, many of the major heat waves and most severe fire seasons in Chile have coincided with La Niña events, as happened in 2017 and 2020.
The combination of global climate change and natural variability of the system is therefore placing the country in a position to more extreme, prolonged and repetitive summersThis scenario forces us to rethink everything from urban and forestry planning policies to public health protocols and agricultural strategies.
With successive heat waves, forest fires at very high risk levels, and agriculture pushed to its limits, Chile has become a clear example of how the Global warming is no longer a distant threat, but an everyday realityWhat is happening today between Coquimbo and La AraucanÃa is reminiscent, in many aspects, of the extreme episodes experienced in recent summers in Spain, Portugal or Greece, and raises urgent questions about how far the capacity for adaptation can go and what measures should be taken, from now on, to protect the population and ecosystems from a heat that no longer seems to be passing.
