How does the sun score work?
Each terrace gets a score from 0–100, calculated from three things: the real position of the sun in Amsterdam's sky for the selected date and time, whether nearby buildings are casting a shadow on that spot (using LIDAR-derived building heights from the Dutch 3D BAG open dataset), and current cloud cover from Open-Meteo. A sun-facing terrace with no obstructions on a clear day scores 100.
How accurate are the shadow predictions?
Directional accuracy is high — the app correctly identifies which side of a street is sunny. Building heights come from Amsterdam's
3D BAG open dataset (LIDAR-derived, accurate to ~0.5m), so shadow lengths are precise for the vast majority of venues. Edge cases (narrow streets, unusual building shapes, awnings, trees) can still affect individual scores — please report any that look wrong.
Does the app use my location?
Only if you allow it. Location is used while the app is open to centre the map and sort terraces by distance. Your coordinates are never sent to our servers — they stay on your device. You can revoke access anytime in Settings → Zonnie → Location.
Where does the weather data come from?
Live cloud cover comes from
Open-Meteo, a free and open meteorological API. Only the terrace's coordinates and the current date are sent — nothing that identifies you.
What is Zonnie Pro?
Zonnie Pro unlocks three features: Time scrubber — drag to set an exact visit window hour by hour and watch scores update live. Google ratings — star ratings and review counts shown inline on every terrace card, so you can find the sunniest and best-rated spot. Unlimited favourites — save as many terraces as you like (free users can save 3). Pro is available as a monthly (€0.99), yearly (€5.99), or lifetime (€17.99) purchase.
My favourite terrace is missing. Can I add it?
Yes! Email us the terrace name and address at
a.j.spilsbury87@gmail.com and we'll add it to the next update. The app currently covers 1,000+ Amsterdam venues — bars, restaurants, and specialty coffee shops — and we're expanding steadily.
The score looks wrong for a terrace I know well.
Shadow prediction isn't perfect, especially on narrow streets or with unusual building shapes. Real-world corrections are genuinely useful — please let us know at
a.j.spilsbury87@gmail.com with the terrace name and what you observed.
How do I clear my favourites or app data?
Favourites are stored only on your device. To clear them, delete and reinstall the app. There's nothing to clear on our end — we don't store any user data on our servers.
Is there an Android version?
Not yet — Zonnie is currently iOS only. An Android version is in development and coming soon. If you'd like to be notified when it launches, drop us an email at
a.j.spilsbury87@gmail.com.
What's a specialty coffee shop vs a "café"?
In Amsterdam "café" usually means a bruine kroeg — a brown bar serving beer. Specialty coffee shops are different: third-wave roasters and brew bars (Lot Sixty One, White Label Coffee, Bocca, Toki, etc). Zonnie tags them separately under the ☕ Coffee filter chip so you can find one without wading through bars.