Client
Ministry of Infrastructure and Water Management + Royal Netherlands Meteorological Institute (KNMI)
Challenge
Redesign an improved weather app to be the best digital solution to accurately warn the Netherlands in case of extreme weather events.
Impact
As a leading weather app, it ensures every Dutch inhabitant access to weather alerts and can prepare for these events accordingly through AA accessibility standards

A public digital solution to navigate weather events
How can we keep citizens safe and up-to-date amidst increasingly unpredictable weather patterns? As the frequency of extreme weather conditions rises, KNMI wants to empower the public with a real-time, accurate and accessible alert system for diverse weather conditions.
Together with KNMI and Egeniq, we led an open-source weather app design that is user-friendly and highly accessible. It features a personalised, location-specific alert system that delivers real-time, relevant weather information. This ensures a seamless user experience while helping citizens stay informed and respond promptly to weather-related risks.
Since November 2024, iOS and Android users can download the renewed app.
Overview of the KNMI App features:
🌦️ Weather information
- Accurate forecasts for your location
- Detailed hourly and daily forecasts
⚡️ Interactive radar maps
- Temperature, precipitation and earthquake tracking
🔔 Weather alerts
- Push notifications for severe weather
- Customisable alert settings
- Advice on what to expect and how to prepare for dangerous weather
💡 Climate insights
- Data on long-term weather trends
- Educational content about climate change

The designers at Koos don't shy away from thinking outside the box and presenting something different than we had envisioned. Always in a pleasant and friendly manner and with the message that we remain the final decision-makers.
Highly accessible and trusted weather app design
KNMI aimed to create a trusted public app that makes extreme weather updates accessible and understandable to everyone, regardless of their abilities or literacy levels. To ensure inclusivity, we conducted user tests with 30 diverse Dutch citizens, varying in age, digital skills and abilities.
By focusing on accessibility and user-centered design, we delivered a highly intuitive and accessible app that meets the needs of a wide range of users and complies with WCAG 2.1 Level AA standards.

Designing for impact at a large scale
To bring KNMI’s mission to life, our multidisciplinary team embraced a flexible design and agile way of working throughout the project.
Over five design sprints, we tackled every essential aspect of the app and its digital structure by:
Our approach
User Research & Validation
We conducted extensive user and accessibility research to validate and improve the solution with diverse users.
Agile & Iterative Development
Our team worked according to the Scrum methodology in sprints, focusing on core features like forecasts, radar maps, notifications and accessibility improvements.
Rapid Prototyping & Feedback Loops
Early prototypes were developed and tested with users to ensure understandability and intuitiveness.
Atomic Design Library
To align the app’s look and feel with the existing KNMI brand, we created an extensive design library (for both iOS and Android).
Stakeholder buy-in
With our stakeholder engagement plan we leveraged desired engagement among various KNMI employees. We organised frequent app demos, where they could ask questions, vote for their fav app icon, and become early app testers.
Next steps
Post-launch, we are committed to continuous optimisation to ensure the app stays efficient and user-friendly. This includes regular accessibility audits to maintain compliance with the highest standards and ongoing updates based on user feedback to enhance functionality and engagement.