COVID-19 Mortality Linked to Weather Factors

Strategic Insights -

Researchers have discovered a significant correlation between COVID-19 mortality rates and weather factors in European countries. According to a study published in the ISPRS International Journal of Geo-Information, the incidence of COVID-19 was substantially negatively correlated with solar insolation in the previous month, indicating that lower levels of sunlight may contribute to increased mortality rates. Additionally, the study found a significant correlation between mortality rates and cloudiness in both the previous month and the respective month, suggesting that weather patterns may play a crucial role in the spread of the virus.

Key Takeaways:

  • Researchers at Carol Davila University of Medicine and Pharmacy investigated the temporal relationship between COVID-19 mortality in European countries and weather factors, including solar insolation and objective sky cloudiness, during the 1st year of the pandemic (March-December 2020).
  • The study found that COVID-19 mortality was substantially negatively correlated with solar insolation in the previous month (std. beta -0.69), indicating a possible link between lower sunlight levels and increased mortality rates.
  • Separate analysis revealed a significant correlation between mortality rates and cloudiness in both the previous month (std. beta +0.14) and the respective month (std. beta +0.32).
  • The time gap of 1 month between COVID-19 mortality and correlated weather factors was previously unreported, suggesting that long-term monitoring of these factors may be important for epidemiological policy decisions.
  • The study suggests that weather patterns may play a crucial role in the spread of COVID-19, particularly in the initial period of a pandemic.
  • The researchers concluded that the long-term monitoring of solar insolation and cloudiness might be important for epidemiological policy decisions, especially in the initial period of potential future pandemics.

Statistics:

  • The study was conducted on European countries in the 1st year of the pandemic (March-December 2020).
  • The correlation between COVID-19 mortality and solar insolation in the previous month was -0.69 (std. beta).
  • The correlation between mortality rates and cloudiness in the previous month was +0.14 (std. beta).
  • The correlation between mortality rates and cloudiness in the respective month was +0.32 (std. beta).

Sources:

  • Spatial and Temporal Correlations of COVID-19 Mortality in Europe with Atmospheric Cloudiness and Solar Radiation. ISPRS International Journal of Geo-Information, 2025,14(8):283. (ISPRS International Journal of Geo-Information - http://www.mdpi.com/journal/ijgi).
  • Medical Letter on the CDC & FDA. Researchers at Carol Davila University of Medicine and Pharmacy Report Research in COVID-19 (Spatial and Temporal Correlations of COVID-19 Mortality in Europe with Atmospheric Cloudiness and Solar Radiation). September 14, 2025; p 244.