KNMI Open Data newsletter January 2023

With this newsletter, we keep you informed on the latest developments at the KNMI Data Platform (KDP). This newsletter focusses on the updates of HARMONIE, our new EDR API and the increasement of the Open Data API key quota. 

Newsletter new style

This year we are starting with a new concept for the newsletter. We will no longer send our newsletter via the mail, but will distribute them through our website. To receive them in your mailbox again, it is important that you register 'again' via the subscribe button on the website. We cannot do this for you due to the legislation. So for the latest news about our portal, please sign up on our Open Data newsletter page. If you have any questions, please send an e-mail to

Open Data newsletter

Improvements HARMONIE coming this summer

The popular weather forecasting model, HARMONIE, is set to receive a major upgrade this summer thanks to the use of the new powerful supercomputer. This update will bring higher resolution and the addition of new parameters, resulting in a more detailed and accurate forecast model. In February the first tests will be run, and in the summer the new version will be published on KDP. The new version will run in parallel with the current version for three months to ensure a smooth transition. Meteorologists and the public alike can expect even more reliable and accurate weather predictions with the new and improved version of the model. Stay tuned for more information on the specific changes and release date of the updated model. 

Current and historical observations now also available via the EDR API

The current and historical observations of all KNMI weather stations are now available via our new EDR API. The data is updated every 10 minutes with the latest current data, with the history going back to 2003. Until now, the current and historical observations of the KNMI weather stations were only available on the KNMI Data Platform per 10 minutes or per month in separate files/datasets. With the new API it is now possible to request the observations of one or more parameters from a specific weather station or location over a certain period. 

The API follows the Environmental Data Retrieval (EDR) standard of the Open Geospatial Consortium. The API returns the data according to the CoverageJSON standard, where several libraries have been created to work with this standard. The API is still in full development and noted as Alpha. Therefore, only data from unvalidated observations is available, and it is not possible to request data for more than a year per request. In addition, not all functionalities of the EDR are built-in as standard. View the documentation and example scripts on our developer portal, to request a token and use the API immediately. If you have any questions or problems with the API, please contact us. 


Quota "Open Data API" key increased

The registered Open Data API key has been given a higher quota. All data can be downloaded with this key, regardless of which dataset. Questions came in whether it was possible to increase this from 200 requests per hour to 1000 requests per hour. The rate limit of 200 per second has remained unchanged. The extra space makes it possible to download for example all 10-minute observations of all measuring stations, a radar product, and other files per day. 

Because the quota in total has become higher than the space you had with all keys combined, the other keys to download data became superfluous. When you have these other keys with the policies "Current 10 Minute Data KNMI Stations" or "Radar Reflectivity Composites", you don't have to do anything. These are still usable and will not be revoked. If you already have an API key with an "Open Data" policy, this key has been increased to 1000 requests per hour. 

Looking back at Knowledge and network day APIs

On 23 November 2022, the Knowledge and network day APIs took place. With over 60 KNMI Open Data users we discussed progress and functionality of the platform. Notably was the diversity of the domains of the participants. This provided the day with a lot of energy and lively conversations. All feedback provides us with ideas for improving the KNMI Data Platform. The presentations from the workshop can be found here

Looking back at Knowledge and network day APIs
Image: ©KNMI

Set up KNMI data user community

An initiative has been launched from the Knowledge and network day APIs to set up the KNMI data user community. We invite all with experience using KNMI data to join and share their knowledge and feedback. By participating in the community, you will have the opportunity to help shape the development of new APIs and improve the overall experience of working with KNMI data. We look forward to building a strong and engaged community that will drive innovation and advancements in the field. To join, please mail to

If you have indicated your interest in the survey sent to participants, you will be invited to the meetings of this initiative. 

New datasets on KDP

The KDP is continuously updated and new datasets and new versions of datasets have been published during the last period. 

New Datasets Abstract
EURADCLIM 24-hour accumulations  Precipitation - The European climatological high-resolution gauge-adjusted radar rainfall (24-hour accumulations) 
EURADCLIM 1-hour accumulations  Precipitation - The European climatological high-resolution gauge-adjusted radar rainfall (1-hour accumulations) 
NAM epos dataset  Seismic datasets collected by NAM between 2013 and 2018 from downhole geophone arrays and flexible networks deployed in the Groningen area
HARMONIE-AROME product 2b Weather model - HARMONIE-AROME KEPS renewable energy parameters, Netherlands 
HARMONIE-AROME product 4a Weather model - HARMONIE-AROME KEPS meteorological parameters, Europe 
HARMONIE-AROME product 4b Weather model - HARMONIE-AROME KEPS renewable energy parameters, Europe 
Ruisdael MRR De Zweth  Precipitation - 10 seconds measurements by Ruisdael Micro Rain Radar (Metek) at De Zweth 
Ruisdael MRR Slufter  Precipitation - 10 seconds measurements by Ruisdael Micro Rain Radar (Metek) at Slufter 


Graphic design: National government

Content: KNMI Open Data team

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