Web App Guide
Conditions & Caching
How data refreshes and where it comes from.
Per-water-body caching
Conditions data is cached per water body and shared across all users at the same location. When you load a spot that another user recently checked, you get their cached result instantly instead of waiting for a fresh API fetch.
Refresh frequency
The cache adapts to how popular a spot is:
| Active users | Refresh interval |
|---|---|
| 6 or more | Every 6 hours |
| 3 to 5 | Every 12 hours |
| 1 to 2 | Every 24 hours |
This keeps busy spots current without burning through API quota on places nobody checks.
The refresh bar
Sometimes you'll see a bar at the top of the page that says something like "Conditions from 4 hours ago. Fetching latest..." with a rotating paddle-themed message. This means the cache for that location is stale and a background refresh is in progress.
The bar disappears automatically when fresh data arrives. The conditions you're seeing are still valid, just not the very latest fetch.
Locations and water bodies
Curated locations link to a canonical water body in the catalog. The water body defines which monitoring stations (USGS, NOAA, and CDEC) provide water data. All users with the same curated spot share one cache entry, so popular lakes like Lake Tahoe stay fresh for everyone.
Offline access
All conditions data is cached on your device automatically. If you lose connectivity or are in a low-reception area, the app shows the last data it fetched along with a banner telling you how old it is.
- Offline banner appears at the top of the screen with the age of the cached data, like "Showing conditions from 2h ago."
- Data freshness timestamps appear on dashboard cards when conditions are more than an hour old.
- Back online confirmation briefly appears when connectivity returns, and data refreshes automatically.
- Location changes (adding, editing, deleting) made while offline will show an error if they can't reach the server. Retry when you're back online.
Cached data never expires. The app will always show you whatever it has, no matter how old, and let you judge whether it's still useful. Timestamps make the age clear.
Data sources
All sources are free public APIs provided by government agencies and open data projects:
- National Weather Service for primary weather forecasts.
- Open-Meteo for full-day coverage and gap filling.
- USGS Water Services for water temperature and streamflow.
- NOAA CO-OPS for tidal data where available.
- CDEC (California Data Exchange Center) for California-specific water data: river stage, reservoir metrics, water quality, and dam releases.