SPEI documentation

SPEI is a Python package designed for calculating drought indices from meteorological and hydrological time series. Built on widely used libraries like Pandas and SciPy, it offers a flexible and simple approach to drought analysis.

This website provides full documentation, example notebooks, and a detailed API reference to help you get started.

The SPEI package is open-source and hosted on GitHub, where you can find more information about the available drought indices and ongoing development. The package is published on PyPi from which it can be installed using pip install spei.

If you use this package for drought analysis and/or visualization, please cite it by referencing our article in the Journal of Open Source Software:

Vonk, M. A. (2025). SPEI: A Python package for calculating and visualizing drought indices. Journal of Open Source Software, 10(111), 8454. doi.org/10.21105/joss.08454.

@article{Vonk_SPEI_2025,
    author  = {Vonk, M. A.},
    doi     = {10.21105/joss.08454},
    journal = {Journal of Open Source Software},
    number  = {111},
    pages   = {8454},
    title   = {{SPEI: A Python package for calculating and visualizing drought indices}},
    url     = {https://joss.theoj.org/papers/10.21105/joss.08454},
    volume  = {10},
    year    = {2025}
}

• Examples
  • Standardized Indices
  • Distributions
  • Drought Prediction with Time Series Modeling
  • Package Comparison
  • Analyzing Multi-Year Droughts
  • Threshold Drought
  • KNMI Drought Indices
  • Rainfall Anomaly Index
  • Article for Journal of Open Source Software
• spei
  • spei package