Former Strava Execs Launch Foggy App Tracking Bay Area Fog in Real Time

Q: How can an app track neighborhood fog in real-time without collecting any personal user data?

An app can do this by relying on environmental data rather than personal data. In Foggy’s case, the core signal comes from public NOAA sources, including GOES satellite imagery and temperature and humidity data, which show where conditions are favorable for fog without identifying any individual user. The privacy challenge is the “last mile”: satellites often cannot reliably tell low clouds from ground-level fog in the Bay Area’s complex terrain. Foggy addresses that with anonymous crowd reports. Users can submit whether fog is present in a general area, but the app says it does not collect personal data, meaning those reports are not tied to a name, account, device profile, or stored movement history. That allows the system to build a neighborhood-level picture by combining broad official weather data with many small, non-identifying observations. In practice, the app can map fog to a coarse location or neighborhood grid, enough to improve accuracy without tracking who sent the report. A privacy-preserving design also means avoiding unnecessary collection such as persistent GPS logs, contact information, or advertising identifiers. Users can simply view a map or manually check an area, while the backend processes satellite and weather feeds and folds in anonymous reports to refine conditions in real time. The result is hyperlocal fog tracking built from public meteorological data and anonymized observations, not from personal surveillance.

1 articles · Updated · SFist · Jul 6

Michael and Macbeth Horvath released Foggy last week, a public app built through Nyfik to map Bay Area fog using live conditions and user reports.
NOAA GOES satellite imagery, plus temperature and humidity data from the Storm Prediction Center, power the tracker, while anonymous crowd reports fill gaps where satellites struggle to separate low clouds from ground fog.
The Outer Sunset couple said they built Foggy to better plan rides, runs and other outdoor time by judging wet conditions, timing and how many layers to bring.
Logan Williams — creator of longtime local tracker Fog Today and an adviser on Foggy — said the app taps a deep Bay Area habit of monitoring fog for activities from cycling to birdwatching.