Analysis of Heatwave Characteristics and Temperature Indices in Karbala City During the Years 2009 to 2024



Gharaee M ; Chaparinia F ; Hadei M
Source: Iranian Journal of Health and Environment Published:2026

Abstract

Background and Objective: Karbala, as one of the world’s largest religious destinations hosting millions of pilgrims annually, is highly vulnerable to extreme heat events. Understanding temperature dynamics and heat-wave characteristics is essential for anticipating climatic risks and protecting public health during mass gatherings. This study aimed to analyze long-term trends in average, minimum, and maximum temperatures and to assess the frequency, duration, and intensity of heat waves in Karbala from 2009 to 2024. Materials and Methods: Daily meteorological data—including maximum, minimum, and mean temperatures—were obtained from the GSOD database. Heat-wave events were identified using the Excess Heat Factor (EHF) index, which incorporates both climatic baselines and population acclimatization. Five indicators (HWN, HWF, HWD, HWM, HWA) were calculated to characterize heat-wave behavior. Linear regression was applied to evaluate temporal trends in temperature and heat-wave metrics. Results: The findings revealed significant increases in annual mean, minimum, and maximum temperatures over the study period. Heat-wave activity intensified, with the number of events and total heat-wave days rising from fewer than 20 days in early years to more than 40 days in several recent years. The longest heat wave extended up to 31 days, and both the intensity and magnitude of heat waves showed an upward trend. These patterns indicate substantial escalation in heat stress conditions consistent with regional warming in the Middle East. Conclusion: Karbala has experienced clear and concerning increases in temperature and heat-wave severity between 2009 and 2024. The intensification of heat-wave frequency, duration, and intensity underscores growing climatic risks—particularly for pilgrims and vulnerable populations during mass gatherings. Strengthening early warning systems, improving cooling infrastructure, increasing green spaces, and implementing heat-health preparedness measures are essential for enhancing resilience and reducing heat-related health impacts in this climate-sensitive city. Copyright © 2026 Iranian Association of Environmental Health and Tehran University of Medical Sciences. Published by Tehran University of Medical Sciences. This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International license (https://creativecommons.org/licenses/by-nc/4.0/). Noncommercial uses of the work are permitted, provided the original work is properly cited.