A newly created actuarial index has positioned the extremes of Spain’s climate at about 1.3 standard deviations, using historical control parameters as a reference.
A new index established by the IAE (Institute of Actuaries of Spain) and called ICAE (the initials of the Spanish Actuarial Climate Index) is able to measure, based on the variation of six specified parameters, what the variability of extreme climate events is.
This tool evaluates heavy rainfall, extreme maximum and minimum temperatures, soil moisture, winds, and sea level provided by Copernicus ERA5. The data offered apply to Spain without including the insular territories or Ceuta and Melilla.
To observe how the index behaves for the extremes in Spain, it was applied to two fairly recent extreme climate events: the wildfire this summer that razed thousands of hectares in Madrid and Ávila and the 2024 Valencia DANA, demonstrating in both cases that the indices were among the most extreme measurements recorded.
Extreme Climate Events and the Tool That Assesses Them
According to the Spanish Extreme Climate Index (ICAE) for climate extremes, the country registered in 2025 the highest level of climate extremes known since 1961. The ICAE combines 6 different climatic indicators to quantify the frequency of these events.
The document was prepared by the Institute of Actuaries of Spain (IAE) and measures the extreme climate values based on six specific variables: maximum temperatures, minimum temperatures, precipitation, drought, wind, and sea level.
The ICAE does not analyze the mean climate; it focuses on studying the climate extremes, examining the statistical distribution of these variables and calculating how much the most intense episodes deviate from a historical reference period, which in this case is the years 1961 to 1990.
The result is expressed in standard deviations (denoted σ) relative to the reference period, which allows comparing different magnitudes such as millimeters per liter or degrees of temperature and presenting them on a single homogeneous scale.
Measurements Carried Out for the ICAE
The analysis of the different variables collects the frequency of maximum temperatures above the 90th percentile and minimum temperatures below the 10th percentile. It also measured the maximum precipitation that accumulated over five consecutive days.
Another parameter was drought, measured through soil moisture loss relative to the reference data. The frequency of episodes of strong winds was also considered, calculated not only in terms of speed but also of power, and finally the variation in sea level was measured.
All these data were standardized and averaged into a single formula, and the experts undertook this based on the Actuarial Climate Index methodology, which was developed in the United States and Canada but adapted to the Spanish geographic and climatic context. The information used comes from the European Union’s Earth observation program, Copernicus.
The assessment of the ICAE shows a clear upward trajectory; after remaining near zero and even displaying negative values for much of the 1970s and 1980s, the index begins a sustained rise from 1990 that, in the last ten years, has intensified and, at the close of 2025, placed the anomaly around 1.3 standard deviations, the highest level of the series since 1961.
Illustrative Data
The IAE tested the measurements of this climate-extremes index by studying two recent episodes: the Valencia DANA of 29/10/24 and the Madrid–Ávila wildfire that occurred in July 2026.
In the Valencia DANA case, the region’s precipitation sub-index reached an anomaly of 2.48 standard deviations, making it one of the most extreme torrential rainfall episodes in the regional historical series. The data also show that such anomalies have become markedly more frequent in the last 8 years than in the previous 22.
Regarding the Madrid–Ávila wildfire of July 2026, the drought sub-index reached 4.7 standard deviations from the reference, the most extreme value recorded in that area, resulting in the reflection of an exceptional soil moisture deficit in the months preceding the fire.
Actuaries argue that the utility of the ICAE goes beyond meteorology, as it can serve as an early warning system to coordinate prevention measures, but it can also be used as a tool for urban planning and to support public awareness, in addition to helping the insurance sector quantify the protection gap against extreme climate risks.
