Online Drought Indicators and Indices

Palmer Hydrological Drought Index (PHDI)


Index name: Palmer Hydrological Drought Index (PHDI).

Ease of use: Yellow.

Origins: Part of the suite of indices developed by Palmer in the 1960s with the United States Weather Bureau.

Characteristics: Based on the original PDSI and modified to take into account longer-term dryness that will affect water storage, streamflow and groundwater. PHDI has the ability to calculate when a drought will end based on precipitation needed by using a ratio of moisture received to moisture required to end a drought. There are four drought categories: near normal, which occurs approximately 28%–50% percent of the time; mild to moderate, which occurs approximately 11%–27% percent of the time; severe, which occurs approximately 5%–10% percent of the time; and extreme, which will occur approximately 4% of the time.

Input parameters: Monthly temperature and precipitation. Information on the water-holding capacity of soils can be used, but defaults are also available. A serially complete record of temperature and precipitation data is required.

Applications: Most useful for taking into account drought affecting water resources on longer timescales.

Strengths: Its water balance approach allows the total water system to be considered.

Weaknesses: Frequencies will vary by region and time of year, where extreme drought may not be a rare event during some months of the year. The impact of human influences, such as management decisions and irrigation, are not considered in the calculations.

Resources: The code can be found in the original Palmer paper in the reference below. More explanations can be found in: Jacobi, J., D. Perrone, L. Lyons Duncan and G. Hornberger, 2013: A tool for calculating the Palmer drought indices. Water Resources Research, 49: 6086–6089. DOI: 10.1002/wrcr.20342.

Reference: Palmer, W.C., 1965: Meteorological Drought. Research Paper No. 45. United States Weather Bureau, Washington, DC.

Currently used by: Trinidad and Tobago.

  1. Aihong Cui
    December 28, 2020 Reply

    Dear Sir/Madam,
    Hi, recently, I built a GRACE-based hydrological drought index from 2002 to 2017 and I want to compare it with PHDI. So could you please provide the data at a global scale if the data has covered the period of 2002-2017 or MatLab code for me to calculate PHDI by myself? Thank you very much in advance.
    Best wishes, Aihong

  2. temesgen mekuriaw
    June 24, 2020 Reply

    Is there any one who can help me?

    1. Katrin Ehlert
      July 8, 2020 Reply

      Dear Temesgen Mekuriaw

      You can pose your question related to the PHDI in this thread and we will respond to you. If you have a more general drought-related question, you can submit it following this link:

      Best regards
      IDMP team

  3. Kendra W
    September 19, 2018 Reply

    Seeking PHDI data for Europe and Argentina if possible.

    1. Robert Stefanski
      September 19, 2018 Reply

      Dear Kendra,

      We will check with our partners whether this data exists.


      1. Kendra Wagner
        January 11, 2019 Reply

        Just checking the status of this request. Is there anywhere else I could be looking?

  4. temesgen
    April 2, 2018 Reply

    what are the hydro logical meteorological agricultural drought indicators & indices ?

    1. Robert Stefanski
      August 8, 2018 Reply

      Dear Temesgen,

      Please take a look at the online Handbook on Drought Indicators and Indices on this website and the PDF version at this link:

      IDMP Team

  5. temesgen fikadie
    February 22, 2017 Reply

    i am Ms c student in engineering hydrology , now i fishiness the course ,but i can not do the thesis/paper ..due to lack of reference books ..research paper and software related to my topic ((((( ASSESSMENT AND EVALUATION OF HYDRO LOGICAL DROUGHT ANALYSIS USING DROUGHT INDEX, IN THE UPPER BLUE NILE BASIN))))))))……so i need from you is that
    1, related books and references ,research papers with detail explained form
    2, software’s …thank you for fast response…!!!!!!

    1. Robert Stefanski
      February 28, 2017 Reply

      Dear Temesgen,

      In the Indices and Indicator Section of the Handbook and on the website, there are a list of References and Resources available. For example, for the PHDI the code can be found at . I will see if there is online version of the reference.


      1. Robert Stefanski
        February 28, 2017 Reply

        Also, please see the following link to the PDHI reference. We have also added the link above.

        Best regards,

        IDMP Team

  6. temesgen fikadie
    January 3, 2017 Reply

    i am a student in Msc in hydrology enginering…so as much as possible please help me..a want your hand

    1. Robert Stefanski
      January 9, 2017 Reply

      Dear Temesgen, Please be more specific with your request. We will send you an email.


  7. temesgen fikadie
    January 3, 2017 Reply

    please send your work on hydrlogical drought analysis based on different drought analysis indce pdf in detail

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