KNMI uses and co-develops HARMONIE. This weather model is used by European meteorological services such as KNMI, for high-resolution short-range numerical weather forecasts. Since 2024, the new version HARMONIE Cy43 has been in use, produced by the United Weather Centres-West (UWC-West) partnership. The weather model produces weather forecasts for such things as temperature, wind, air pressure and precipitation. It calculates the parameters up to 60 hours ahead, with a resolution of 1 hour. HARMONIE is issued generically for the Netherlands, Europe and a Caribbean domain.
Goal HARMONIE
Weather forecasts are calculated by computer models that describe the development of the real atmosphere using mathematical equations. HARMONIE is mainly developed by a European consortium for short-term weather forecasts. Within this consortium, each national weather service has its own national responsibilities and corresponding competencies in safety, including warnings, preparedness and defense. KNMI's HARMONIE weather model is therefore also available in three different versions covering the geographical area of the Netherlands, Europe and the Caribbean. The model focuses on events that occur on a small scale but can have serious consequences, for example, extreme precipitation such as cloudbursts and rapidly changing low-level thunderstorms.
HARMONIE Cy43 technical documentation
On June 20, 2024, KNMI began operational runs of HARMONIE from Cycle 43 at UWC-West after a one-year test period. We provide datasets for three areas: The Netherlands, Europe and the Caribbean. The Dutch and European domains are cutouts of the DINI domain (Denmark, Ireland, Netherlands, Iceland), which was created from the collaboration within UWC-West. A separate run is made for the Caribbean, which is expanded to include Suriname compared to the previous version. This run also includes the domains for both the Windward and Leeward Islands.
These datasets are only available for the entire domain. We do not, in accordance with our legal framework, offer cutouts for specific locations or parameters.
Data set (on KDP) Domin Run Max. vertical height Parameters HARMONIE Cy43 P1 Netherlands Deterministic 300 Meteorological HARMONIE Cy43 P2a Netherlands Ensemble 10 Meteorological HARMONIE Cy43 P2b Netherlands Ensemble 300 Renewal energie HARMONIE Cy43 P3 Europe Deterministic 300 Meteorological HARMONIE Cy43 P4a Europe Ensemble 10 Meteorological HARMONIE Cy43 P4b Europe Ensemble 300 Renewal energie HARMONIE Cy43 P5 Europe Deterministic 550 Selection HARMONIE Cy43 BES Caribbean Deterministic 1000 Meteorological HARMONIE Cy43 L20
(soon available)Europe Deterministic 10 North Sea applications Image: © KNMI / KNMI
On the left is the DINI domain, with Europe (red) containing the 2.0 km lat-lon cutout around the Netherlands (green) and the 5.5 km rotated lat-lon cutout covering almost the entire area (blue). On the right is the Caribbean domain, with the entire domain (light blue) and the Leeward Islands (brown) and Windward Islands (gray)
Filename and times
A new weather forecast is available every hour. The files are compressed into .tar. Extracted, the file names follow the following convention:
HA43_TTT_YYYMMDDhhmm_lllll_GB
- TTT is for file type: N20 is the Dutch domain, N55 is the DINI/EU domain, L20 is the original resolution DINI/EU domain
- YYYYMMDDhhmm is the date and time of the forecast
- lllll is the current time span in hours within the prediction of time intervals of +00h (+1h) +60h
Dutch and European (DINI) domain
The Dutch domain is the green outline on the left figure below. It has the full HARMONIE resolution (~2x2 km). The grid is a regular lat-lon grid with a grid spacing of about 2 km (longitude: 0.01 degrees; latitude: 0.029 degrees).
The European domain is the blue outline on the left figure below and is the full domain of DINI. It is a rotated lat-lon grid with a reduced resolution of 0.05 degrees, with meteorological parameters available at normal altitudes (above the surface) and at pressure levels.Caribbean domain
The files in the Caribbean dataset are divided into BESS, BOV and BEN. BESS covers the entire Caribbean region, BOV is the domain for the Dutch Windward Islands, and the BEN is the domain for the Dutch Leeward Islands. The Caribbean domain now includes Suriname and provides broader coverage for the region, and is the bright green outline on the right figure above. The coordinates of the new domain are from -3 to 24.45 degrees (latitude) and from -79.5 to -42.55 degrees (longitude) in 0.05-degree increments. This results in a grid with 740 points in latitude and 550 points in longitude.
Image: © KNMI / KNMI
Visual presentation ensemble members in HARMONIE. Member 0 is in every run, the other members have an off-set in time when run. To have to have a full ensemble, users could combine them with a delay to a full ensamble of 30 members with a total weather forecast of 54 hours.
Ensemble data are processed in batches of 5 members (MBR). Each batch uses the latest ECMWF analysis as input.
- Member 1 to 5 at hour 1
- Member 6 to 10 at hour 2
- Member 11 to 15 at hour 3
- Member 16 to 20 at hour 4
- Member 21 to 25 at hour 5
- Member 26 to 30 at hour 6
This setup ensures that 5 ensemble members are generated every hour, each starting at that specific hour. Unlike traditional ensembles where a full set is started at a single time, we now continuously generate subsets, creating a rolling ensemble prediction.
To have a full set of ensemble data like ECMWF, it is necessary to clip 5 to 0 hours at the beginning of the forecast horizon and add 0 to 5 hours at the end of the forecast horizon (See image below).
Special considerations for accumulated parameters
To avoid overestimates, it is necessary, for accumulated parameters such as precipitation, to subtract precipitation from the first shared hour of the ensemble members. Each batch of ensemble members starts at a different hour. Careful adjustment is thus required to ensure accurate values for the accumulated data. Other parameters, such as temperature and wind, can be used as they are for each ensemble member without further adjustment.
HARMONIE data is stored in the GRIB1 format, a standard from the World Meterological Organization (WMO). Therefore, we recommend using a grib decoder that fits the grib code table associated with the corresponding grib files. A decoder that fits the KNMI HARMONIE files is an open source package ecCODES which can be downloaded from the ECMWF. An overview of GRIB codes that fit the KNMI data can be found in the tables below.
Here is a summary of the GRIB codes for HARMONIE Cy43 P1. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.
Table with GRIB codes for data set HARMONIE Cy43 P1 Code Abbreviation Parameter description Unit Leveltype Level TRI 1 PMSL Pressure altitude above mean sea level Pa 103 0 0 1 PSRF Pressure height above ground Pa 105 0 0 6 GP Geopotential m2 s-2 105 0 0 11 TMP Temperature K 105 0, 2, 50, 100, 200, 300 0 11 ISBA Temperature of nature tile
(per 18-11-24)K 105 800(0cm), 801(-7cm), 802(-50cm) 0 17 DPT Dew-point temperature K 105 2 0 20 VIS Visibility m 105 0 0 33 UGRD u-component of wind m s-1 105 10, 50, 100, 200, 300 0 34 VGRD v-component of wind m s-1 105 10, 50, 100, 200, 300 0 52 RH Relative humidity % 105 2 0 61 APCP Total precipitation kg m-2 105 0 4 65 WEASD Water equivalent of accumulated snow depth kg m-2 105 0 0 66 SD Snow depth m 105 0 0 67 MIXHT Mixed layer depth m 105 0 0 71 TCDC Total cloud cover % 105 0 0 73 LCDC Low cloud cover % 105 0 0 74 MCDC Medium cloud cover % 105 0 0 75 HCDC High cloud cover % 105 0 0 81 LAND Landcover Proportion 105 0 0 111 NSWRS Net short-wave radiation flux (surface) J m-2 105 0 4 112 NLWRS Net long-wave radiation flux (surface) J m-2 105 0 4 117 GRAD Global radiation flux J m-2 105 0 4 122 SHTFL Sensible heat flux J m-2 105 0 4 132 LHTFL Latent heat flux through evaporation J m-2 105 0 4 162 CSULF U-momentum of gusts out of the model m s-1 105 10 2 163 CSDLF V-momentum of gusts out of the model m s-1 105 10 2 181 LPSX (Cumulative sum) Rain kg m-2 105 0 4 181 LPSX Rain kg m-2 105 0 0 184 HGTY (Cumulative sum) Snow kg m-2 105 0 4 184 HGTY Snow kg m-2 105 0 0 186 ICNG Cloud base m 200 0 0 201 ICWAT (Cumulative sum) Graupel kg m-2 105 0 4 201 ICWAT Graupel kg m-2 105 0 0 201 ICWAT (Column integrated) Graupel kg m-2 200 0 0 Here is a summary of the GRIB codes for HARMONIE Cy43 P3. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.
Table with GRIB codes for data set HARMONIE Cy43 P3 Code Abbreviation Parameter description Unit Leveltype Level TRI 1 PMSL Pressure altitude above mean sea level Pa 103 0 0 1 PSRF Pressure height above ground Pa 105 0 0 6 GP Geopotential m2 s-2 105 0 0 6 GP Geopotential m2 s-2 100 300, 500, 700, 850, 925 0 11 TMP Temperature K 100 300, 500, 700, 850, 925 0 11 TMP Temperature K 105 0, 2, 50, 100, 200, 300 0 17 DPT Dew-point temperature K 105 2 0 20 VIS Visibility m 105 0 0 33 UGRD u-component of wind m s-1 100 300, 500, 700, 850, 925 0 33 UGRD u-component of wind m s-1 105 10, 50, 100, 200, 300 0 34 VGRD v-component of wind m s-1 100 300, 500, 700, 850, 925 0 34 VGRD v-component of wind m s-1 105 10, 50, 100, 200, 300 0 52 RH Relative humidity % 100 300, 500, 700, 850, 925 0 52 RH Relative humidity % 105 2 0 61 APCP Total precipitation kg m-2 105 0 4 65 WEASD Water equivalent of accumulated snow depth kg m-2 105 0 0 66 SD Snow depth m 105 0 0 67 MIXHT Mixed layer depth m 105 0 0 71 TCDC Total cloud cover % 105 0 0 73 LCDC Low cloud cover % 105 0 0 74 MCDC Medium cloud cover % 105 0 0 75 HCDC High cloud cover % 105 0 0 81 LAND Landcover Proportion 105 0 0 111 NSWRS Net short-wave radiation flux (surface) J m-2 105 0 4 112 NLWRS Net long-wave radiation flux (surface) J m-2 105 0 4 117 GRAD Global radiation flux J m-2 105 0 4 122 SHTFL Sensible heat flux J m-2 105 0 4 132 LHTFL Latent heat flux through evaporation J m-2 105 0 4 162 CSULF U-momentum of gusts out of the model m s-1 105 10 2 163 CSDLF V-momentum of gusts out of the model m s-1 105 10 2 181 LPSX (Cumulative sum) Rain kg m-2 105 0 0 181 LPSX Rain kg m-2 105 0 4 184 HGTY (Cumulative sum) Snow kg m-2 105 0 0 184 HGTY Snow kg m-2 105 0 4 186 ICNG Cloud base m 200 0 0 201 ICWAT (Cumulative sum) Graupel kg m-2 200 0 0 201 ICWAT Graupel kg m-2 105 0 0 201 ICWAT Graupel kg m-2 105 0 4 Here is a summary of the GRIB codes for HARMONIE Cy43 P5. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.
Table with GRIB codes for data set HARMONIE Cy43 P5 Code Abbreviation Parameter description Unit Leveltype Level TRI 1 PSRF Pressure height above ground Pa 105 0 0 6 GP Geopotential m2 s-2 105 0 0 11 TMP Temperature K 105 0 0 11 TMP Temperature K 109 1-90 0 33 UGRD u-component of wind m s-1 109 1-90 0 34 VGRD v-component of wind m s-1 109 1-90 0 51 SPFH Specified humidity kg kg-1 109 1-90 0 HARMONIE Cy43 P2a/P4a
Here is a summary of the GRIB codes for HARMONIE Cy43 P2a/P4a. Both HARMONIE Cy43 P2a and HARMONIE Cy43 P4a contain the same set of variables. The difference is that P2a is for the Dutch domain, and P4a is the entire DINI domain at a lower resolution. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.
Table with GRIB codes for data set HARMONIE Cy4 P2a/P4a Code Abbreviation Parameter description Unit Leveltype Level TRI 1 PMSL Pressure altitude above mean sea level Pa 103 0 0 11 TMP Temperature K 105 2 0 20 VIS Visibility m 105 0 0 33 UGRD u-component of wind m s-1 105 10, 50 0 34 VGRD v-component of wind m s-1 105 10, 50 0 52 RH Relative humidity % 105 2 0 65 WEASD Water equivalent of accumulated snow depth kg m-2 105 0 0 71 TCDC Total cloud cover % 105 0 0 73 LCDC Low cloud cover % 105 0 0 74 MCDC Medium cloud cover % 105 0 0 75 HCDC High cloud cover % 105 0 0 162 CSULF U-momentum of gusts out of the model m s-1 105 10 2 163 CSDLF V-momentum of gusts out of the model m s-1 105 10 2 181 LPSX Rain kg m-2 105 0 4 184 HGTY (Cumulative sum) Snow kg m-2 105 0 4 186 ICNG Cloud base m 200 0 0 201 ICWAT (Cumulative sum) Graupel kg m-2 105 0 4 209 MIXLY Lightning - 200 0 0 HARMONIE Cy43 P2b/P4b
Here is a summary of the GRIB codes for HARMONIE Cy43 P2b/P4b. Both HARMONIE Cy43 P2b and HARMONIE Cy43 P4b contain the same set of variables. The difference is that P2b is for the Dutch domain, and P4b is the entire DINI domain at a lower resolution. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.
Table with GRIB codes for data set HARMONIE Cy43 P2b/P4b Code Abbreviation Parameter description Unit Leveltype Level TRI 33 UGRD u-component of wind m s-1 105 10, 50, 100, 200, 300 0 34 VGRD v-component of wind m s-1 105 10, 50, 100, 200, 300 0 71 TCDC Total cloud cover % 105 0 0 11 TMP Temperature K 105 2 0 117 GRAD Global radiation flux J m-2 105 0 4 HARMONIE Cy43 BESS
Here is a summary of the GRIB codes for HARMONIE Cy43 BESS. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.
Table with GRIB codes for data set HARMONIE Cy43 BESS Code Abbreviation Parameter description Unit Leveltype Level TRI 1 PMSL Pressure altitude above mean sea level Pa 103 0 0 6 GP Geopotential m2 s-2 100 500 0 11 TMP Temperature K 100 500 0 11 TMP Temperature K 105 2 0 17 DPT Dew-point temperature K 105 2 0 33 UGRD u-component of wind m s-1 100 200, 500, 700, 850, 925 0 33 UGRD u-component of wind m s-1 105 10 0 34 VGRD v-component of wind m s-1 100 200, 500, 700, 850, 925 0 34 VGRD v-component of wind m s-1 105 10 0 73 LCDC Low cloud cover % 105 0 0 74 MCDC Medium cloud cover % 105 0 0 75 HCDC High cloud cover % 105 0 0 116 SWAVR Short-wave radiation flux J m-2 105 0 0, 4 117 GRAD Global radiation flux J m-2 105 0 4 160 CSUSF CAPE J kg-1 105 0 0 161 CSDSF AROME hail diagnostic % 105 10 0 162 CSULF U-momentum of gusts out of the model m s-1 105 10 2 163 CSDLF V-momentum of gusts out of the model m s-1 105 10 2 165 CFNLF Convective inhibition (CIN) J kg-1 105 0 0 181 LPSX (Cumulative sum) Rain kg m-2 105 0 0, 4 184 HGTY (Cumulative sum) Snow kg m-2 105 0 0, 4 187 LTNG Cloud top m 200 0 0 201 ICWAT (Cumulative sum) Graupel kg m-2 105 0 0, 4 HARMONIE Cy43 BOV/BEN
Here is a summary of the GRIB codes for HARMONIE Cy43 BOV/BEN.
Table with GRIB codes for data set HARMONIE Cy43 BOV/BEN Code Abbreviation Parameter description Unit Leveltype Level TRI 1 PMSL Pressure altitude above mean sea level Pa 103 0 0 11 TMP Temperature K 105 2 0 17 DPT Dew-point temperature K 105 2 0 33 UGRD u-component of wind m s-1 105 10 0 34 VGRD v-component of wind m s-1 105 10 0 51 SPFH Specific humidity kg kg-1 105 2 0 52 RH Relative humidity % 105 100, 250, 500, 750, 1000 0 71 TCDC Total cloud cover % 105 0 0 73 LCDC Low cloud cover % 105 0 0 74 MCDC Medium cloud cover % 105 0 0 75 HCDC High cloud cover % 105 0 0 76 CWAT Cloud water kg m-2 109 65 0 116 SWAVR Short-wave radiation flux J m-2 105 0 0, 4 117 GRAD Global radiation flux J m-2 105 0 4 161 CSDSF AROME hail diagnostic % 105 0 0 162 CSULF U-momentum of gusts out of the model m s-1 105 10 2 163 CSDLF V-momentum of gusts out of the model m s-1 105 10 2 181 LPSX (Cumulative sum) Rain kg m-2 105 0 0, 4 181 LPSX Rain kg m-2 109 65 0 184 HGTY (Cumulative sum) Snow kg m-2 105 0 0, 4 201 ICWAT (Cumulative sum) Graupel kg m-2 105 0 0, 4 Here is a summary of the GRIB codes for HARMONIE Cy43 L20. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.
Table with GRIB codes for data set HARMONIE Cy43 L20 Code Abbreviation Parameter description Unit Leveltype Level TRI 1 PMSL Pressure altitude above mean sea level Pa 103 0 0 11 TMP Temperature K 105 2 0 17 DPT Dew-point temperature K 105 2 0 33 UGRD u-component of wind m s-1 105 10 0 34 VGRD v-component of wind m s-1 105 10 0 61 APCP Total precipitation kg m-2 105 0 4 71 TCDC Total cloud cover % 105 0 0 81 LAND Landcover Proportion 105 0 0 115 LWAVR Long-wave radiation flux J m-2 105 0 4 117 GRAD Global radiation flux J m-2 105 0 4 124 UFLX Momentum flux, u-component N m-2 105 760(sea) / 770 (lakes) 0 125 VFLX Momentum flux, v-component N m-2 105 760(sea) / 770 (lakes) 0 LevelType
Table with definitions for leveltype Level type WMO/HIRLAM type definition Units 100 Isobaric level hPa 103 Specified altitude above mean sea level Altitude in m 105 Specified height above ground Altitude in m 109 Hybrid level 200 Entire atmosphere (considered as a single layer) TRI (TimeRangeIndicator)
Table explaining TRI Time Range Indicator Range 0 Instant 2 Accumulated over limited period 4 Accumulated over entire forecast period Due to the growing popularity of the HARMONIE Cy43 P1 dataset the decision has been made to not only provide access to the most recent files but also start to build up an archive from 8 January 2026 onward. This will not be done retroactively but all files starting from January 8th will now be available.
For the other HARMONIE datasets we retain only the last 72 hours of data on KNMI Data Platform. KNMI Data Platform does not provide archival data for these HARMONIE datasets. The reason is that files are too large and after a while they no longer contain current meteorological information. To maintain our commitment to providing a free platform, our policy is to remove this data to reduce costs.If you are interested in archival data from KNMI HARMONIE model runs, please contact the KNMI licensing office (licentiebureau@knmi.nl). Since this will be a personalized product, there are costs associated.
If you are interested in a longer period of HARMONIE model data, you can use the HARMONIE reforecast dataset with data from October 2020 till September 2023.
There are also (free) alternatives available outside KNMI, for example the ERA5 Reanalysis Product or the Alliander Weather API