SPI-6 values for 331 Divisional Secretariat divisions of Sri Lanka (1981–2024)
This dataset contains the 6-month Standardized Precipitation Index (SPI-6) monthly time series for all 331 Divisional Secretariat (DS) divisions of Sri Lanka, spanning 1981 to 2024. SPI-6 values were computed using the SPI_SL_6.exe software, developed in line with World Meteorological Organization (WMO) recommendations, from monthly precipitation data interpolated across the 331 DS-divisions via Kriging from 62 meteorological stations operated by the Department of Meteorology, Sri Lanka. The dataset supports the manuscript "SPI-Based Spatiotemporal Drought Frequency and Trends across the Divisional Secretariat Divisions in Sri Lanka" (Pramudi et al., submitted to Natural Hazards and Earth System Sciences, manuscript ID egusphere-2026-5234), which uses these SPI-6 values to derive drought frequency across five severity categories and to assess long-term monotonic trends at the DS-division scale using the Mann–Kendall test and Sen's slope estimator.