# CoastWarn — NOAA coastal flood alerts > Coastal flood alert app using NOAA data with customizable thresholds. (iPhone/iPad app by Ryan Dean.) - Source: https://appshunter.io/ios/app/coastwarn/id6798089542 (this page in markdown: same URL + `.md`) - Developer: [Ryan Dean](https://appshunter.io/developer/1850630498) - Category: Weather, Travel - Price: Free with in-app purchases - Rating: 5.00/5 from 1 App Store ratings - Age rating: 4+ - Requires: iOS 17.0 · 3 MB - Languages: American English - Released: 2026-09-22 - Data updated: 2026-10-03 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/coastwarn/id6798089542/reviews.md ## What is CoastWarn? CoastWarn monitors official NOAA water-level data and alerts you when observed levels reach the threshold you set. If you live, work, or keep a boat on the coast, you know the drill: nuisance flooding that soaks your car, a dock line that needs more slack, a driveway that disappears at high tide. CoastWarn helps you keep track of the water levels that matter to you. HOW IT WORKS - Find a supported NOAA station using your ZIP code or the station map. - Set the water-level threshold that matters to your property or boat. - Receive flood alerts and all-clear notifications, with current readings and trends. - See “Flood Expected” notices when supported regional forecasts predict your threshold will be reached. BUILT FOR COASTAL REALITY - Official NOAA CO-OPS water-level observations and tide predictions. - Adjustable alert thresholds at eligible stations. - Time-sensitive notifications for minor-or-higher flood alerts, subject to your iPhone’s notification settings. - Tide charts and regional model projections where available. - Alert history, monitoring status, and notices when monitoring is interrupted. WHO IT’S FOR Waterfront homeowners · boaters and marina tenants · coastal businesses · anyone who lives with a rising tide TRY IT FREE CoastWarn is free for 7 days. Continue with CoastWarn Pro Lifetime: a single $19.99 purchase that unlocks the app’s features with no subscription or renewal. No user account required. Restore Purchases is available in Settings. Data, forecasts, and alert monitoring vary by station. Alert delivery depends on current data, connectivity, notification permissions, and iOS scheduling. CoastWarn supplements official warnings; always follow National Weather Service guidance and local emergency instructions. ## Key features - Customizable flood alert thresholds - NOAA water-level monitoring - Tide charts and predictions - Flood expected notifications - Alert history - Station map search ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | CoastWarn Lifetime Unlock | $19.99 | one-time | ## Frequently asked questions about CoastWarn ### What is CoastWarn? CoastWarn is an application that monitors official NOAA water-level data and sends you alerts when observed levels reach a threshold you set. It helps users stay informed about potential coastal flooding. ### How does CoastWarn work? You can find supported NOAA stations by ZIP code or map, then set a water-level threshold. CoastWarn will then send you flood alerts and 'all-clear' notifications with current readings and trends. ### What data does CoastWarn use? CoastWarn utilizes official NOAA CO-OPS water-level observations and tide predictions. It also provides regional model projections where available. ### Is CoastWarn free to use? CoastWarn offers a 7-day free trial. After the trial, you can continue using its features with a one-time purchase of $19.99 for CoastWarn Pro Lifetime, which requires no subscription. ### What devices does CoastWarn support? CoastWarn is currently available for iPhone. It requires iOS notification settings to be enabled for timely alert delivery. ### How often is CoastWarn updated? The latest version, 1.1.0, was released on September 28, 2026, with the initial release on September 22, 2026. Update frequency is typically tied to data availability and feature enhancements. ### Does CoastWarn have ads? No, CoastWarn does not contain advertisements. The app is ad-free, with monetization coming from a one-time purchase for Pro features. ### What is the age rating for CoastWarn? CoastWarn has an age rating of 4+. This indicates it is suitable for a wide range of users, including children, for general weather information. ## Version history (last 2 releases) ### 1.1.0 — 2026-09-28 Flood alerts - Alert details now show when NWS says the hazard ends, and say "Ended" once it has. - When NWS gives no end time, the app shows when NWS will next update the alert. - Alert details now include the NWS instructions (precautionary and preparedness actions) whenever NWS sends them. - NWS text keeps its tide tables and road lists laid out as NWS wrote them. Tides - High and low tide rows show the forecast peak, so they match your flood alert. When the forecast peak differs from the NOAA tide table by 15 minutes or more, the row shows the tide table time too. - A tide that has already peaked no longer shows as the next high. - Chart time labels no longer overlap. Fewer false alarms about monitoring - Water level gauges often report 12 to 18 minutes late. CoastWarn now waits until a reading is 45 minutes old before it warns you about a missed update or shows the reading's age. Notices during an active flood alert are never delayed. ### 1.0.0 — 2026-09-22 No release notes. ## Apps similar to CoastWarn | App | Rating | Price | Category | | --- | --- | --- | --- | | [WBOC Weather](https://appshunter.io/ios/app/wboc-weather/id762861353) | 4.7 (6,750) | Free | Weather | | [Rain Tally: Virtual Rain Gauge](https://appshunter.io/ios/app/rain-tally-virtual-rain-gauge/id6462464149) | 4.5 (465) | Free | Weather | | [WindAlert: Wind & Weather Map](https://appshunter.io/ios/app/windalert-wind-and-weather-map/id317992025) | 4.8 (4,661) | Free | Weather | | [Ambient Weather Network](https://appshunter.io/ios/app/ambient-weather-network/id1426025887) | 4.6 (13,418) | Free | Weather | | [Northern Light Aurora Forecast](https://appshunter.io/ios/app/northern-light-aurora-forecast/id1092949787) | 2.7 (208) | Free | Weather | | [ForeFlight Mobile EFB](https://appshunter.io/ios/app/foreflight-mobile-efb/id333252638) | 4.4 (3,246) | Free | Weather | --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-03.*