Keywords: lightning, thunderstorm activity, lightning strike density, spatio-temporal distribution, lightning detection

This article presents the results of calculations and analysis of the spatio-temporal distribution of “cloud-ground” lightning strikes in Ukraine during the period 2017–2021, based on data from the lightning detection system of the Ukrainian Hydrometeorological Institute, which includes 12 sensors located in different regions of the country. The total number of ground lightning strikes and their density (number of lightning strikes per 1 km² - l/km² ) within each administrative region were analyzed. The average lightning density over the five-year period was 0.89 per 1 km², with an average annual number of approximately 539,000 lightning strikes. The highest lightning densities were observed in Odesa (1.34 l/km²), Zaporizhzhia (1.15 l/ km²), Mykolaiv (1.14 l/km²), Ivano-Frankivsk (1.08 l/km²), Vinnytsia (1.05 l/km²), and Zakarpattia (1.05 l/km²) regions. The lowest values were recorded in Sumy (0.54 l/km²), Kharkiv (0.59 l/km²), Chernihiv (0.63 l/km²), and Volyn (0.65 l/km²) regions. The greatest total number of lightning strikes across Ukraine was registered in 2018 (658,000), while the lowest was in 2020 (322,000). It was additionally established that the seasonal maximum of thunderstorm activity occurs in June–July, when the most intense convective systems are formed. Regional differences in the intensity of cloud-to-ground lightning discharges are based on the combination of thermodynamic and orographic factors. The analysis of interannual variability revealed a strong dependence of lightning occurrence on the type of atmospheric circulation and the conditions favorable for the development of atmospheric convection. The obtained results enhance the understanding of contemporary features of thunderstorm activity in Ukraine and can be used to assess territories in terms of lightning strike risk, improve early-warning systems, and support safety planning. Furthermore, they may serve as a basis for further research in climate monitoring and the analysis of extreme atmospheric phenomena.

1. Velychko, S. A. (2014). Seasonal variability of thunderstorm activity in Ukraine in relation to the features of atmospheric circulation. Ukrainian Hydrometeorological Journal, 14, 47–55.

2. Matsuk, Y. M. (2013). Changes in thunderstorm activity in Ukraine during the 20th and early 21st centuries. Bulletin of V. N. Karazin Kharkiv National University. Series 'Geology. Geography. Ecology', 39, 147–151.

3. Chernokulsky, A., Shikhov, A., Yarinich, Y., & Sprygin, A. (2023). An empirical relationship among characteristics of severe convective storms, their cloud-top properties, and environmental parameters in Northern Eurasia. Atmosphere, 14(1), Article 174.

Feldmann, M., Blanc, M., Brennan, K. P., Thurnherr, I., et al. (2025). European supercell thunderstorms – an underestimated current threat and an increasing future hazard. arXiv preprint arXiv:2503.07466v1 [physics.ao-ph].

4. Feldmann, M., Blanc, M., Brennan, K. P., Thurnherr, I., et al. (2025). European supercell thunderstorms – an underestimated current threat and an increasing future hazard. arXiv preprint arXiv:2503.07466v1 [physics.ao-ph].

5. Pilorz, W., Taszarek, M., Kolendowicz, L., et al. (2024). Comparing ERA5 convective environments associated with hailstorms in Poland between 1948–1955 and 2015–2022. Atmospheric Research, 298, Article 107179.

6. Kholoptsev, A. V., & Matsuk, Y. M. (2012). Analysis of current trends in the spatio-temporal variability of thunderstorm day recurrence in Ukraine. Human and Environment. Problems of Neoecology, 1–2, 13–19.

7. Nedostrelova, L. V., & Chumachenko, V. V. (2021). Temporal distribution of thunderstorms at the AMSU Odessa at the beginning of the 21st century. Ukrainian Hydrometeorological Journal, 27, 16–23.

8. Fedoniuk, V. V., Fedoniuk, M. A., & Pavlus, A. M. (2021). Thunderstorm activity research in Volyn and Ukraine based on Blitzortung online resources. Bulletin of Lesya Ukrainka East European National University. Series: Geographical Sciences, 9, 37–46.

9. Poręba, S., Taszarek, M., & Ustrnul, Z. (2022). Diurnal and seasonal variability of ERA5 convective parameters in relation to lightning flash rates in Poland. Weather and Forecasting, 37(8), 1447–1467.

10. Agayar, O., Gospodinova, K., Shmakin, A., & Martius, O. (2024). Precipitation extremes in Ukraine from 1979 to 2019: Climatology, large-scale flow conditions, and moisture sources. Natural Hazards and Earth System Sciences, 24(2), 411–432.

11. Kryvobok, A. A., Kryvoshein, A. O., Koman, M. M., & Krupa, E. O. (2018). Ukrainian segment of the ENTLN lightning detection system. Ukrainian Hydrometeorological Journal, 21, 45–53.

12. Zabolotna, O. S., Kryvoshein, O. O., Kryvobok, O. A., & Krupa, E. O. (2025). Spatio-temporal distribution of dangerous dry thunderstorms in Ukraine. Ukrainian Geographical Journal, 2(130), 38–46. https://doi.org/10.15407/ugz2025.02.038

13. Pinto Neto, O., Pinto, I. R. C. A., & Pinto, O. Jr. (2020). Lightning during the COVID-19 pandemic in Brazil. Journal of Atmospheric and Solar–Terrestrial Physics, 211, Article 105463. https://doi.org/10.1016/j.jastp.2020.105463

14. Gole, P. K., & Midya, S. K. (2021). Association of pre-monsoon CG lightning activity and some surface pollutants in different Indian cities around the COVID-19 lockdown year 2020. Proceedings of the Indian National Science Academy, 87(4), 657–667. https://doi.org/10.1007/s43538-021-00052-3

15. Liu, X., et al. (2024). Reduction in global lightning activity during the COVID-19 pandemic (preprint). Research Square.

16. Pérez-Invernón, F. J., Huntrieser, H., Gordillo-Vázquez, F. J., & Soler, S. (2021). Influence of the COVID-19 lockdown on lightning activity in the Po Valley. Atmospheric Research, 263, 105808. https://doi.org/10.1016/j.atmosres.2021.105808Latham, J., Blyth, A., Christian, H., Deierling, W., Dye, J., Gadian, A., et al. (2021). Global warming and lightning flash rate. AGU Fall Meeting Abstracts, AE12A-02.

17. Yusfiandika, F., Lim, S. C., Gomes, C., Chockalingam, A., & Cheng Pay, L. (2021). Lightning behaviour during the COVID-19 pandemic [version 3; peer review: 2 approved]. F1000Research, 10, Article 906. https://doi.org/10.12688/f1000research.70650.3

18. Blunden, J., & Boyer, T. (Еds.). (2021). State of the Climate in 2020. Bulletin of the American Meteorological Society, 102(8), S1–S475. https://doi.org/10.1175/2021BAMSStateoftheClimate.1

19. Schumann, U., Füllekrug, M., & Satori, G. (2025). Contributions of lightning to long-term trends and inter-annual variability in global atmospheric chemistry constrained by Schumann resonance observations. Atmospheric Chemistry and Physics, 25(14), 8929–8951. https://doi.org/10.5194/acp-25-8929-2025

20. Lipinsky, V. M. (2003). Climate of Ukraine. Kyiv: Raevsky Publishing House