NOISELESS: making Belgium’s long climate records more consistent and accessible

A century-long climate record is invaluable. But making it scientifically consistent takes careful work. Now available through the Belgian Climate Data Portal, NOISELESS provides homogenised monthly temperature and precipitation series for Belgium, with records extending from 1880 to 2024.

Separating climate signals from changes in observations

Over the lifetime of a weather station, instruments may be replaced, observation practices may change, or the station itself may move. Changes in its surroundings can also affect measurements. These non-climatic influences can introduce artificial breaks into a record, making it harder to assess how the climate has actually changed.

NOISELESS addresses this challenge through homogenisation: identifying and correcting abrupt, non-climatic shifts in long observational series. The resulting data provide reference material for analysing climate trends in Belgium. The corrections target abrupt changes, however, and do not remove gradual biases.

Explore the NOISELESS dataset and user guide.

What went into creating the dataset?

Producing the monthly series first required aggregating daily observations. For temperature, each monthly value represents the average of the daily minimum or maximum temperatures. For precipitation, it represents the total rainfall recorded during the month. These are therefore monthly climate records, not daily datasets.

The homogenisation work involved grouping series for analysis, checking outliers, detecting breaks and applying corrections. The accompanying Product User Guide documents these methods, alongside the input data, station-event metadata and geographical and temporal coverage.

The dataset was developed through collaboration between the Royal Meteorological Institute of Belgium and the Belgian Climate Centre, which coordinate the NOISELESS project, with VITO as a project partner. The project is funded through the Copernicus Climate Change Service’s National Collaboration Programme. C3S is implemented by ECMWF on behalf of the European Commission.

What can the data be used for?

The station-level series provide a basis for examining long-term temperature and precipitation trends at observation locations across Belgium. The dataset includes both historical records covering 1880-2024 and a denser network of series covering the second half of the twentieth century through to 2024.

National and sub-regional series are also available as supplementary information on climate signals over larger areas. Their interpretation requires care: reliability depends on the variable and the region considered, and broader conclusions should not be drawn from these regional series alone without specialist climate expertise.

Find the data and the documentation in one place

NOISELESS is available through the Belgian Climate Data Portal, alongside its user guide, station information, maps and correction records.

The portal brings together climate-related datasets that would otherwise remain scattered across Belgian institutions and research projects. It helps users find, share and explore data, while connecting datasets to their authors and related publications.

Explore the NOISELESS dataset and user guide.