El Niño 2026: What Catastrophe Bond Investors Should Watch

After several years dominated by La Niña conditions, the return of El Niño is once again commanding attention from weather, insurance, and capital markets. However, the most recent reports are sounding the alarm on just how strong El Niño will be this year: it has a 63% chance of becoming a very strong event that could disrupt global weather patterns and hotter climates, according to the National Oceanic & Atmospheric Administration.

We recently explored El Niño through the lens of hurricane season in a previous blog. However, El Niño influences more than just hurricanes, and it’s equally important to understand the cascading effect it will have on secondary perils like flooding and drought.

Let’s first take a step back to see what experts are predicting for El Niño this year. El Niño is characterized by warmer-than-average sea surface temperatures in the central and eastern Pacific Ocean, but this year it arrives on unusually warm ocean temperatures across the globe. This could amplify weather extremes and make it harder to measure this year’s event against previous years or modeling assumptions.

For the United States, one region to watch closely is Southern California. Historically, strong El Niños have been associated with wetter-than-average winters across California, particularly in the southern region. In fact, for two of the last four “very strong” El Niños on record, California experienced more than double its annual rainfall. While additional rainfall can provide relief from drought conditions, it can also increase the risk of flooding, landslides, mudflows, and infrastructure damage, especially in areas recently affected by wildfires. Burn scars often leave hillsides vulnerable, allowing heavy rainfall to trigger destructive debris flows with little warning. And this risk is adjacent to rising sea-levels that cause high tides that can amplify flooding.

Flood risk remains one of the most challenging perils for catastrophe modelers and investors alike. Unlike hurricanes, which can often be tracked days in advance, flooding losses are highly dependent on localized rainfall patterns, soil saturation, topography, and urban development. As a result, an active El Niño year may introduce more uncertainty when it comes to insurance and reinsurance portfolios.

Heavy rainfall doesn’t just indicate more possible flooding either. El Niño could also increase wildfire risk in the Northwestern U.S. Increased rainfall is a catalyst for grass and brush to grow, while hotter climates risk drying them out, which potentially makes the vegetation dangerous kindling if and when the heat returns.

Most catastrophe bonds have historically focused on peak perils such as U.S. hurricanes and earthquakes. However, the market has gradually expanded to include a broader range of risks such as those discussed above, in addition to severe storms, winter freezes, and more. Given this, an El Niño-driven increase in precipitation could potentially influence both insured loss activity and investor sentiment regarding weather-related risks.

On the other hand, El Niño's effects don’t universally signal bad news for cat bond performance. The same atmospheric changes that can increase rainfall in California have historically been associated with reduced Atlantic hurricane activity due to stronger upper-level wind shear. Lower hurricane frequency can be beneficial for bonds exposed to U.S. tropical cyclone risk, potentially offsetting concerns arising from other regions or perils. When looking at El Niño through the context of a cat bond, it’s important to understand what perils the bond covers, where, and what its triggers are to get the best idea of how the projected weather patterns could impact your portfolio.

As always, catastrophe bond investors should avoid relying solely on seasonal climate forecasts. El Niño is an important piece of the puzzle, but it is only one factor among many that shape insured catastrophe losses. A disciplined approach that considers peril diversification, trigger structures, and underlying exposure remains the most effective way to navigate an increasingly complex climate environment.

Sources

CNN

Inside Climate News

LA Times

National Ocean Service