Delft Measures Rain

When it rains in natural areas, rain drains to the soil or moves to bigger rivers via smaller ones. When it rains in the city all the water that hits houses or streets must be drained via gutters and sewerage. Climate change causes an increase in the intensity of rainfall, especially during summer. During a very short period it will rain so much that the sewerage cannot handle the large amount of water. On the street, large puddles are formed and even flooding occurs. Nice to play in, but not very convenient.

Researchers of the TU Delft are researching the rainfall patterns in the city. Is it raining as much at every location or does it rain less or more in some places? To map the amount of rainfall across the city, we need the help from the citizens of Delft!


Between July and September of 2020, we received 1991 measurements from 95 participants. These data were subsequently analysed by TU Delft student Illias Timori, guided by principal investigator Marie-Claire ten Veldhuis. The results are promising! Not only did we receive a lot of data, but most of the data is as reliable as the official KNMI (Royal Dutch Meteorological Institute) data. Because the KNMI has a lot less rain gauges per square kilometer, Delft Measures Rain provides a higher resolution of rain measurements within Delft. That is exactly what we were looking for! You can find an overview of the most important results in the infographic. All data can be found on our data map.

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Between July 18 and September 2020 citizens of Delft will measure the amount of rain on a daily basis. As a researcher for Delft Measures Rain you will receive a (Dutch) manual and measuring kit from WaterLab, with which you create your own rain gauge. You will then measure the daily amount of rain in a period of your choosing.


With this research the citizens of Delft assist the TU Delft in mapping the changing rainfall patterns that result from climate change. All inhabitants of Delft can join this project! You will get a biweekly update with info about the weather, water in Delft and inspiration to get to action yourself and fight flooding or droughts. In addition, your data will be part of the scientific dataset. 

Variability in rainfall across the city

Marie-Claire ten Veldhuis is a researcher of the TU Delft and investigates how cities influence local rainfall patterns. The amount of rainfall can differ for every neighborhood, despite the relatively small distances between them.

Marie Claire ten Veldhuis / TU Delft
Jeff Davids / Smartphones4Water

The Royal Dutch Meteorological Institute (KNMI) measures rainfall throughout the Netherlands and on average has 1 rain gauge per 100 km2. In total, there are 300 gauges throughout the country. Apps, like Buienradar (RainRadar), predict and measure the rainfall for every 1 km2. However, the rainfall is measured in an indirect manner, and the results are often not really precise. 

During Delft Measures Rain, we try to increase the number of rain gauges, so that we can do a daily measurement for every km2 of Delft. We aim to do at least 1 measurement per km2 of the city for the duration of 2 months. 

Who and where?

Delft Measures Rain is a collaboration between TU Delft, the municipality of Delft, Smartphones4Water and WaterLab.