Lightning protection is a constant need for buildings, industrial sites, and critical infrastructure. However, major climatic mechanisms can redistribute conditions favorable to thunderstorms depending on the region and season. Among these, El Niño is one of the most closely monitored.
In 2026, this phenomenon is once again prominent. While it doesn't allow us to predict the impact of each lightning strike on a given location, it does help us understand why atmospheric convection can change on a large scale. This first part explains the ENSO mechanism; the next article will address its connection to electrical activity and lightning protection more directly.
ENSO: The climate system behind El Niño
ENSO, for El Niño–Southern Oscillation, is a coupling between the ocean and the atmosphere in the equatorial Pacific. Specifically, sea surface temperatures, winds, and areas of tropical rainfall mutually influence each other.
This system has three phases. Thus, they do not describe three "storm seasons", but three background configurations that modify climatic probabilities on a seasonal scale.
- El Niño is the warm phase: the surface waters of the central and eastern equatorial Pacific are warmer than normal.
- La Niña is the cold phase: temperature anomalies and part of the atmospheric organization reverse, without the regional impacts being perfectly symmetrical.
- The neutral phase corresponds to the absence of an El Niño or La Niña phase declared according to the operational thresholds; it does not imply the absence of thunderstorms or the absence of extreme events.
Therefore, simply stating that a year is "under El Niño" is insufficient to describe the weather of a country, let alone that of a specific location. Other climatic patterns, local conditions, and the day's weather situation remain crucial.
How does El Niño take hold?
In near-normal conditions, the trade winds —regular east-west winds near the equator—push warm surface waters westward across the Pacific. Furthermore, this movement promotes the upwelling of colder, nutrient-rich waters along the coast of South America: this is known asupwelling, or the movement of deep water up into the atmosphere.
The warm water reservoir located to the west then more easily feeds evaporation, clouds, and convective rainfall in the vicinity of Indonesia and the western Pacific. Thus, the ocean and atmosphere maintain a large-scale circulation.
- The trade winds usually carry warm waters westward.
- Contrasts in surface temperature help to organize tropical atmospheric circulation.
- Convection refers to the upward movement of warm, humid air that promotes the formation of deep clouds and thunderstorms.
DuringEl Niño, the trade winds weaken or become disturbed. As a result, warm water extends further towards the central and eastern Pacific, while the upwelling of cold water may decrease.
The area of convection is also shifting. NOAA indicated in its bulletin of July 9, 2026, that convection was strengthened over the central and east-central Pacific, and suppressed over Indonesia. This shift is crucial: it does not mean "more thunderstorms everywhere," but rather a redistribution of environments conducive to thunderstorms.
An irregular cycle, measured by several indicators
ENSO typically recurs every 2 to 7 years , and an episode often lasts 9 to 12 months, according to the World Meteorological Organization (WMO). However, each event differs in its intensity, duration, development season, and interactions with other oceanic or atmospheric mechanisms.
To monitor the evolution of the phenomenon, climatologists rely on complementary indicators. In particular, they avoid reducing a complex situation to a single thermometer.
- Niño-3.4 is the sea surface temperature anomaly in a central area of the equatorial Pacific, between 5°N–5°S and 170°W–120°W.
- ONI, or Oceanic Niño Index, is a three-month moving average of Niño-3.4 anomalies, traditionally used by NOAA to characterize episodes.
- SOI, or Southern Oscillation Index, measures a pressure contrast between Tahiti and Darwin; a negative value is usually consistent with El Niño.
These indicators must be interpreted in conjunction with observations of wind, cloud cover, and precipitation. Indeed, the classification of an ENSO episode relies on ocean-atmosphere coupling, not on an isolated temperature anomaly.
Which El Niño events have marked recent history?
The episodes of 1972–1973, 1982–1983, 1997–1998, 2015–2016, and 2023–2024 are frequently cited as major hot spots. However, comparing their "strength" without specifying the index, the reference period, and the methodology can be misleading.
Measurement tools, observation networks, and operational definitions have evolved. It is therefore more accurate to consider them as historical milestones rather than as a definitive classification.
- 1972–1973 helped to raise awareness of the possible global repercussions of a warm Pacific episode.
- 1982–1983 and 1997–1998 are often studied for their strong oceanic and atmospheric anomalies.
- 2015–2016 prompted much research on the interactions between El Niño, global heat and convective activity.
- 2023–2024 reminds us that the impacts also depend on the background climate context and regional conditions.
Furthermore, the term "super El Niño" is primarily used in the media. The WMO uses an operational classification that includes the "very strong" ; therefore, using the first term requires clearly presenting it as an informal designation.
What is the state of El Niño in August 2026?
According to the NOAA/CPC bulletin of July 9, 2026, an El Niño was established and strengthening. The weekly Niño-3.4 index reached +1.2°C, with widespread warm anomalies in the central and eastern Pacific.
The same bulletin assessed the probability of persistence until the beginning of spring 2027 at 97% . Furthermore, NOAA estimated the probability of a "very strong" El Niño in October–December 2026 at 81%
- These figures come from the bulletin of July 9, 2026, available before the publication of this article on August 12, 2026.
- They express probabilities of ENSO scenarios, not a probability of lightning striking an installation.
- NOAA bulletins and WMO updates should be followed regularly, as seasonal forecasts change.
TheWMO reiterated on July 31, 2026, that the intensity, duration, and interactions with other climate drivers determine regional effects. Therefore, this situation calls for informed vigilance, not automatic conclusions about a particular territory.
Does El Niño cause more thunderstorms and lightning?
Not uniformly or automatically. El Niño shifts the areas where warm, humid air can rise, thus altering environments favorable to convection; depending on the region and season, the signal can be positive, negative, or weak.
Lightning is linked to deep convective clouds and processes such as humidity, instability, updrafts, and cloud microphysics. Therefore, a warm anomaly in the Pacific does not directly translate into a predetermined number of lightning strikes in a country or at a specific location .
- A Dowdy study, based on 1996–2013 satellite data between 35°N and 35°S, found a significant correlation between Niño-3.4 and local lightning activity in 53% of grid cells for at least one season.
- This relationship showed opposite signs depending on the area: it confirms a redistribution, not a universal increase.
- A seasonal forecast is useful for preparing operations; however, it does not replace real-time detection and warning.
The next article will detail these results, global maps of electrical activity, and their operational implications. In the meantime, the most robust strategy remains the same across all ENSO phases: understand the actual site exposure, apply a risk analysis, and maintain the protective measures.
Why does lightning protection remain a priority?
Storm patterns change, but the objective of protection remains the same: to reduce the consequences of a lightning strike and associated power surges. Therefore, an international approach based on IEC62305 provides a framework for risk analysis and the design of appropriate protection.
An installation never becomes invulnerable. However, coordination between external protection, grounding, Equipotential Spark Gap and surge protection can reduce the risk to people, structures and equipment.
- An emission(ESE) lightning rod is one of the possible solutions depending on the study and the applicable framework.
- Surge protection devices complement external protection to limit the effects on electrical and electronic networks.
- The inspection, maintenance and updating of the risk analysis must take into account the evolution of the use of the site and its environment.
Therefore, an automatic protection class should not be inferred from El Niño. Each sizing decision requires site data, documented analysis, and solutions designed by qualified professionals. For ESE protection in France, the applicable standard is NF C 17-102.
Monitor observed activity to make better decisions
Climate indicators provide a seasonal and global view. However, operating a site also requires an understanding of the actual activity measured around its facilities.
To monitor the impact of this potentially intensified storm activity on your facilities, the LPS Manager products LPS France and link detected events, equipment status, and maintenance actions. The website lpsmanager.io presents the solution; product management is performed within the application.
- Centralize information useful for monitoring multiple sites.
- Document events and facilitate maintenance decisions.
- Supplement seasonal forecasts with operational data and real-time alert procedures.
Key points to remember
El Niño is a warm phase of the ENSO system that redistributes ocean temperatures, winds, and tropical convection. In August 2026, data from the July 9 NOAA bulletin indicated a strengthening episode, but it did not predict a lightning strike at a specific location.
Vigilance must therefore remain international, local and continuous: understanding major climate signals, monitoring observed activity and sustainably protecting installations according to IEC 62305. In the next article, we will examine how studies on convection and lightning allow us to interpret these changes without overgeneralizing them.
Sources
- NOAA Climate Prediction Center, ENSO Diagnostic Discussion, July 9, 2026.
- World Meteorological Organization, “Strong El Niño expected to intensify”, July 31, 2026.
- Dowdy, AJ (2016), Seasonal forecasting of lightning and thunderstorm activity, Scientific Reports.
- NOAA CPC, ENSO evolution and index definitions (document accessed on August 9, 2026).
