SPI & SPEI Calculation Toolkit

A Python toolkit for computing the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) for drought monitoring and analysis. The toolkit supports daily-resolution calculations for both point-based time series and grid-based datasets, with multiple accumulation periods and statistical distributions, including Gamma, Pearson III, Fisk, and Gaussian Mixture Models. Grid-based calculations are compatible with Xarray datasets, making the toolkit suitable for both research and operational workflows.