Whenever El Niño in Costa Rica comes up, many people remember droughts, low rivers, and crops battered by heat. With the second half of 2026 on the horizon, it is worth understanding what this phenomenon is, how it usually shows up in the country, and what we can do now, without alarmism and with good information.
What El Niño is, explained without jargon
El Niño is the warm phase of a natural climate pattern in the Pacific Ocean called ENSO (El Niño-Southern Oscillation). It occurs when surface waters in the central and eastern equatorial Pacific warm above normal for several months. That warming alters atmospheric circulation and changes where it rains more and where it rains less across much of the planet.
It is neither a new nor a strange phenomenon: it occurs irregularly, roughly every two to seven years, with varying intensities. Some episodes are weak and almost go unnoticed; others, like the 2015-2016 event, leave a mark on agriculture, water, and energy.
An important clarification about 2026
Climate forecasts are probabilities, not certainties. A probability that El Niño will develop does not mean it will happen, or that, if it does, it will have the same strength or the same effects as in previous years. That is why the most reliable source for following its evolution is the National Meteorological Institute (IMN), which issues updated analyses and warnings for the country.
How it usually affects Costa Rica
Historically, El Niño episodes tend to leave a different pattern on each side of the country:
- North and Central Pacific, and the Central Valley: less rain than expected during the rainy season, a more pronounced «veranillo de San Juan» (mid-year dry spell), and a higher risk of water deficit.
- Caribbean region and the northern zone: a greater likelihood of above-average rainfall and, at times, localized flooding.
- Temperatures: a tendency toward hotter days and a higher heat index, especially in lowland areas.
These are trends, not absolute rules. Each event has its own particularities, and other factors, such as tropical systems or cold fronts, also influence the country’s weather.
The second half of the year: why it matters so much
From May to November, Costa Rica’s Pacific side goes through its rainy season, and aquifers, reservoirs, and annual-cycle crops depend on it. If rainfall falls short in those months, the impact may be felt later in the dry season, when water reserves are already more strained.
In addition, the second half of the year coincides with the Atlantic hurricane season. In El Niño years, Atlantic cyclone activity is usually lower, which can reduce certain storms, although that does not completely eliminate extreme events or the effects of Pacific systems.
Agriculture and livestock: the most exposed
The agricultural sector is among the first to notice the changes. Crops such as rice, sugarcane, corn, beans, and pasture for livestock depend on the rainfall regime. A water deficit can reduce yields, raise animal feed costs, and increase heat stress.
Some measures that institutions and specialists usually recommend:
- Adjust planting dates according to seasonal forecasts.
- Opt for more drought-tolerant varieties.
- Harvest rainwater and improve irrigation efficiency.
- Cover the soil with crop residue or ground cover to retain moisture.
- Plan forage and water reserves for livestock.
At home and in the community
Although the phenomenon may seem distant, its effects reach everyday life: water rationing, higher electricity use due to heat, or price increases for some foods. Preparing does not require large investments, just sensible habits:
- Take care of water: fix leaks, reuse it when possible, and avoid watering during the hottest hours.
- Store with good judgment: keep a moderate reserve for emergencies, without hoarding.
- Protect your health: stay hydrated, avoid prolonged sun exposure, and pay attention to children, older adults, and people with chronic illnesses.
- Reduce fire risks: avoid burning, especially in areas with dry grass.
- Save energy: heat increases the use of fans and air conditioners, so it is best to use them efficiently.
The role of institutions
In situations of possible drought or excess rainfall, several entities step in: the IMN with meteorological information, the National Commission for Risk Prevention and Emergency Response (CNE) with risk management, the Ministry of Agriculture and Livestock (MAG) with support for the productive sector, and water institutions, such as AyA, with supply planning. Staying alert to their announcements is the best way to avoid rumors and hasty decisions.
Useful information, not fear
El Niño is a reminder that we live in a country that is very sensitive to climate variability. Rather than asking whether the phenomenon will be strong or weak, the practical question is how prepared we are for a year with less rain in some areas and more in others.
Following official reports, using water responsibly, and planning ahead are simple actions that, added up across households, communities, and producers, make a real difference. For the second half of 2026, the best strategy remains the same: stay well informed, anticipate, and act calmly.