New plugin – Evapotranspiration and plugin updates


A new plugin is now available which calculates an estimate of daily evapotranspiration using the modified FAO Penman-Monteith equations.

This plugin uses several parameters (daily avg temperature, humidity, pressure, elevation, day of the year, latitude, solar radiation, wind speed, height of wind speed measurement) to estimate the daily evapotranspiration.

By default it loads your current station data (if you do not have solar sensor, then this value is set to 0 and you should make an estimate). You can change the values and also units (which should adapt to your config.php by default).

It uses the Penman-Monteith set of equations, which comprises of over 20 formulae to estimate daily evapotranspiration. Please keep in mind this is the first version and it is possible that the calculation is not 100% accurate (it is an estimate!). In addition to evapotranspiration, it also calculates mean saturation vapor pressure, actual vapor pressure derived from humidity, vapor pressure deficit, day of the year, inverse relative distance Earth-Sun, solar declination, sunset hour angle, extraterrestrial radiation, daylight hours, clear-sky solar radiation, net solar shortwave radiation, net long-wave radiation and net radiation).


  • download, unzip, upload to server and add link to the menu



The following two plugins have recently been updated:

  • SNOW 2.0 – new version now also includes Snow Index calculations and graphs
    – if updating you only need to replace reports.php, reportSeason.php and allSeasons.php files – therefore your original page with settings can stay as is and no need to set up anything
  • CONTACT FORM – some bugs fixed, for example the name can now include spaces
    – simply replace the contact.php, which does not require any setting up. The other file where you changed your email etc. can stay as is.

2 thoughts on “New plugin – Evapotranspiration and plugin updates

  1. Saludos Jachym

    Thank you for your new plugin dedicated to evapotranspiration.

    I think we should make a small modification to the “et.php” file so you do not always give the value 0

    Line 43:

    if ($ solar) {

    should be modified by:

    if ($ solarSensor) {

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