About openmeteo.org


Openmeteo.org is a project devoted to the development of free hydrological and meteorological software and to the collection and distribution of free hydrological and meteorological data.

Public Database

An international, public database with free hydro-meteorological data offers anyone the possibility to upload their own data.

Client software: Hydrognomon

Developed by the National Technical University of Athens since 1998, Hydrognomon is time series management and processing software for the demanding professional and amateur alike. A simple executable file with no dependencies, Hydrognomon is free software, available under the GNU General Public License version 3, runs under MS Windows and, with Wine, in i386 Unixes such as Linux on i386.

Server software: Enhydris

Hydrognomon uses plain text files to store data. Users and organizations who need a database to manage their time series but do not want to use the openmeteo.org database can use Enhydris: server software that keeps a database of measuring stations, instruments and time series, with a web interface. Enhydris is the software that powers the openmeteo.org site. It is distributed, which means that many organisations can keep their own server each but share a common portal. Enhydris is cross-platform free software, available under the GNU General Public License version 3.

Developer area

If you want to participate in the development of Hydrognomon or Enhydris or report bugs, please visit our GitHub page.


For any questions, contact us at openmeteo@itia.ntua.gr.

History and credits

The ITIA research team of the National Technical University of Athens, lead by professor Demetris Koutsoyiannis, has been developing databases for hydrological time series since 1990. Over the years we have experimented and worked with ever changing technologies. We have used various RDBMS's (INGRES, Oracle, MS Access, InterBase, MySQL, PostgreSQL, SQLite) and several programming languages (C, VB, Object Pascal, Perl, Python). As we have developed large and small databases and processing software, our data storing techniques have matured, and are still evolving.

The concept of openmeteo.org, that is, a publicly accessibly database of free data, offered together with free software, was an idea with which we have been experimenting since the early 2000's. An early version was developed in 2003 and failed.

In 2009, we were assigned the improvement of the National Databank of Hydrological and Meteorological Information, a project with which we had also been involved in the past. The time was now ripe to put emphasis on free software. We used the funding not only on technical improvements, but also on the effort required to make the software free. Hydrognomon, our flagship product, is now free software. Enhydris was developed from scratch, and of course it is free software. The development of Enhydris proceeded not strictly within the pressing needs of the National Databank, but also with openmeteo.org in mind. In 2011, openmeteo.org was ready for use by the public.

This is the list of people, organizations and companies who made openmeteo.org possible:

Antonis Christofides (openmeteo.org founder, system administrator, and initial developer of Hydrognomon and Enhydris)

Stefanos Kozanis (principal maintainer of Hydrognomon, Enhydris, and openmeteo.org)

George Karavokiros (Enhydris developer)

Demetris Koutsoyiannis, Nikos Mamassis (scientific advisors)

Antonis Koukouvinos (GIS consultant)

Katerina Tzouka, Sandra Baki, Yiannis Markonis, Hristos Tyralis, Evangelos Rozos, Panayiotis Dimitriadis, Andreas Efstratiadis (administrative help and quality control)

National Technical University of Athens (our institution, which also provides hosting)

Ministry of Public Works and the Hydroscope Systems Consortium (funders)

GEOSET Ltd (Michalis Salachoris and partners; GIS consultants)

Indifex (Dimitris Glezos, Andreas Loupasakis, Seraphim Mellos; subcontractors who developed Enhydris)