At the end of the year, we traditionally add a new stripe to the climate barcode: the series of colored lines that show how the temperature in the Netherlands has changed since 1901. The stripe for 2025 is dark red. This year, De Bilt ranks in the top 10 warmest years. Seven years from the past decade (2016-2025) are in that top ten. A clear sign of warming in the Netherlands.
What does the climate barcode show?
The climate barcode consists of vertical lines, each stripe representing a year in the long temperature measurement series in De Bilt. Since 1901, the temperature has been recorded daily here. The color of the stripes indicates the annual average temperature. Blue shades correspond to relatively cool years, red shades to relatively warm years.
Each stripe represents a year in the long temperature measurement series in De Bilt.
Karin van der Wiel, who creates the climate barcode for the Netherlands every year, explains, “The stripe effect shows the fluctuations in weather from year to year. The long-term warming is visible in the overall image: at the beginning of the series, cooler blue shades dominate, while towards the end, increasingly deep red shades appear.”
2025 in the barcode
Around the turn of the year, when nearly all temperature measurements are completed, the new stripe for 2025 is added to the climate barcode. The annual average temperature in 2025 is 11.4 degrees. Although 2025 is not a record year in the Netherlands, it ranks in the top 10 warmest years. The new stripe is therefore red.
In recent decades, many annual averages have clearly exceeded the level of the early twentieth century, causing new stripes to mostly fall in the red zone. Thus, 2025 fits into a longer trend of an increasingly warmer Dutch climate.
Part of a bigger picture
Dutch warming and the climate barcode are part of a global warming picture. The climate barcode method was developed by climate scientist Ed Hawkins to visually and simply represent the global temperature trend.
The Dutch climate barcode aligns with other analyses of climate change in the Netherlands, such as the KNMI’23 climate scenarios, which show that temperatures will continue to rise in the coming decades, and the recent report on weather extremes. Climate change is no longer an abstract concept but clearly visible in Dutch measurement series.
Climate stripes 1901-2025
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Downloads
Download the KNMI climate barcode 1901-2025 as a chart (pdf) or as an image (pdf). The measurement data can be viewed on the KNMI Climate Dashboard. The (preliminary) weather overview for 2025 will be published on Tuesday, December 30.