Assessment of Rainfall Variability, Meteorological Drought Characteristics and Agricultural Implications Using SPI, Rainy Days and Trend Analysis in Hyderabad, India

Abstract

Background: Rainfall variability and meteorological drought are major concerns in semi-arid regions such as Hyderabad, where agricultural planning and water-resource management depend strongly on the amount and distribution of monsoon rainfall. Aims: This study assessed rainfall variability, meteorological drought characteristics and agricultural implications in Hyderabad, India, using the Standardized Precipitation Index (SPI), rainy-day analysis, the Mann–Kendall trend test and Sen’s slope estimator. Study Design: A quantitative climatic data analysis was conducted using historical rainfall records. Place and Duration of Study: Hyderabad, Telangana, India, using daily rainfall data for the period 2003–2024. Methodology: Daily rainfall observations obtained from the India Meteorological Department were aggregated to monthly and annual scales. SPI values were computed to identify wet and dry conditions and to classify drought severity. Annual rainy days, defined as days with measurable rainfall of at least 2.5 mm, were used to examine rainfall distribution. The Mann–Kendall test and Sen’s slope estimator were applied to assess the direction, significance and magnitude of rainfall-related trends. Results: Rainfall conditions showed marked inter-annual variability during 2003–2024. Of the 22 years analysed, 12 years (54.55%) had dry conditions (SPI < 0), while 10 years (45.45%) had wet conditions (SPI > 0). Moderate drought occurred in 2 years (9.09%), and no severe drought events were identified. The Mann–Kendall analysis indicated a positive but statistically non-significant SPI trend (p > 0.05), while Sen’s slope showed a marginal increase of about +0.01 SPI units per year. Annual rainy days varied from 47 to 102 days, indicating considerable variability in rainfall frequency and distribution. Conclusion: Hyderabad experienced recurrent dry years and substantial rainfall variability rather than a clear long-term wetting or drying trend. The findings highlight the need for climate-resilient crop planning, efficient water management, drought preparedness and improved use of climate information in rainfed and water-sensitive agricultural systems.