Shifting Seasonality in a Changing Climate: Implications for Actuarial Practice

Published June 2, 2026

Author

Peter Sousounis, Ph.D.

Overview

Shifting seasonality is important to understanding how risk manifests across natural, economic, and human systems. This report explores how shifting seasonality may influence a wide range of societal outcomes, including health risks, agricultural productivity, infrastructure resilience, and retirement behavior.

Key Findings

The Society of Actuaries Research Institute’s Catastrophe and Climate Strategic Research developed this report to bring together a variety of ideas and approaches in understanding shifting seasonality.

By integrating climate science with actuarial expertise, the insurance industry can serve a critical role in helping society understand and manage the evolving risks associated with a changing climate. These changes challenge traditional assumptions about the reliability of historical data. As seasonal boundaries shift and extreme events become more variable, actuarial models may need to incorporate forward-looking climate information, scenario analysis, and new data sources.

FAQ

Question: Why is it necessary to understand seasonality in terms of climate?

Answer:
Seasonality has long served as a foundation for understanding climate, ecosystems, and economic activity. Climate change is altering the timing and characteristics of seasonal patterns in ways that have important implications for risk management.

Question: Why is seasonality of interest to insurers?

Answer:

For insurers and actuaries, seasonal signals embedded in historical data have long helped differentiate expected loss patterns from anomalies. This perspective is relevant in providing evidence of seasonal shifts. Evolving conditions continue to reshape expectations and outcomes.

Material

Shifting Seasonality in a Changing Climate: Implications for Actuarial Practice

Suggested Citation

Sousounis, Peter. Shifting Seasonality in a Changing Climate: Implications for Actuarial Practice. Society of Actuaries Research Institute, May 2026. https://www.soa.org/resources/research-reports/2026/shifting-seasonality-changing-climate/

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