# PredictWind vs Slackwater

The clearest difference is ratings volume: PredictWind at 33K against Slackwater's 1. PredictWind also leads on update cadence (every 9 days vs monthly) and chart position (#23 vs unranked). Slackwater's advantage is review sentiment (100% vs 84%) and rating (5.0 vs 4.8). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. PredictWind sells 10 in-app purchases, starting at $6.99 per month and Slackwater sells 2 in-app purchases, starting at $7.99 per year. Whichever you choose, the download price is not the number that matters.

Slackwater holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: PredictWind has 33K ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 84% of PredictWind's written reviews are positive against 100% of Slackwater's.

PredictWind ships an update every 9 days, Slackwater monthly. The most recent releases landed on November 13, 2026 and November 11, 2026 respectively.

## The numbers

| Metric | PredictWind | Slackwater |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.8 (33K ratings)](https://appshunter.io/ios/app/predictwind-marine-forecasts/id477048487/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/slackwater-tides-and-currents/id6813654837/reviews)** |
| Number of ratings | **33K** | 1 |
| Positive reviews | 84.4% of reviews | **100.0% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 9 days** | Monthly |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Best chart rank | **#23** | — |
| Size | 111 MB | 59 MB |
| Requires iOS | **16.0** | 26.0 |
| Devices | iPhone, iPad | **iPhone, iPad, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [PredictWind Limited](https://appshunter.io/developer/477048590) | [Open Water Software LLC](https://appshunter.io/developer/1887683238) |

## What reviewers say

### PredictWind

[App page](https://appshunter.io/ios/app/predictwind-marine-forecasts/id477048487)

**Currently charting:** #23 Top Grossing · Weather, #68 Top Free · Weather (US App Store)

Get detailed marine weather forecasts, including wind, wave, tide, and current predictions. Compare multiple global weather models and access high-resolution maps. Optimize your routes and plan departures with AI-powered insights and historical climate data.

**Highlights:** Multiple global weather model comparison, High-resolution forecast maps, AI-powered weather routing, Departure planning tools, Tidal and ocean current maps, 10-day forecast and climate data, Live wind observations and webcams

**Features:** Vision Pro support

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Basic - Monthly | $6.99 | per month |
| Basic - 3 Monthly | $12.00 | per 3 months |
| Basic - Annual | $29.00 | per year |
| Standard - Monthly | $49.00 | per month |
| Standard - 3 Monthly | $99.00 | per 3 months |
| Professional - Monthly | $99.00 | per month |
| Standard - 3 Monthly | $99.00 | per 3 months |
| Standard - Annual | $249.00 | per year |
| Professional - 3 Monthly | $249.00 | per 3 months |
| Professional - Annual | $499.00 | per year |

**What reviewers like**

- 👍 Accurate weather forecasts
- 🚀 Comprehensive data and features
- 💡 Useful for sailing, fishing, and other outdoor activities
- 👍 Easy to use and navigate
- 🚀 Reliable and dependable

**What reviewers complain about**

- 🐛 Occasional inaccuracies in weather predictions
- 💰 Expensive subscription costs
- 🔒 Difficult to cancel subscription
- 🔒 Locked into using proprietary hardware and services
- 🔒 Limited free features

**Reported bugs**

- App crashes or freezes on some devices
- Inconsistent performance across different locations
- Subscription issues and billing problems

**Requested features**

- Improved integration with other apps and charts
- More frequent weather model updates
- Earlier weather forecast updates
- Ability to customize alert settings
- Improved offline functionality


### Slackwater

[App page](https://appshunter.io/ios/app/slackwater-tides-and-currents/id6813654837)

This app provides tide and current predictions that work offline, even without a signal. It offers detailed information on tide times, current speeds and directions, and celestial events for thousands of stations worldwide. Users can access this data on their iPhone, iPad, and Apple Watch.

**Highlights:** Offline tide and current data, Tide predictions for 5,000+ stations, Current speed and direction, Sunrise, sunset, and moon phase, Apple Watch app and widgets, Siri integration

**Features:** macOS Compatibility, Family Sharing, Apple Watch app, Vision Pro support, iPhone Duo support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Yearly | $7.99 | per year |
| Premium Lifetime | $69.99 | one-time |


## Frequently asked questions

### Is PredictWind free?

PredictWind is free to download, with in-app purchases available.

### Is Slackwater free?

Slackwater is free to download, with in-app purchases available.

### Which has better reviews, PredictWind or Slackwater?

Slackwater is rated higher. PredictWind averages 4.8 out of 5 from 33K ratings, while Slackwater averages 5.0 from 1 ratings.

### Do PredictWind or Slackwater have ads?

Neither PredictWind nor Slackwater shows ads.

### Which is updated more often, PredictWind or Slackwater?

PredictWind ships an update every 9 days, and Slackwater monthly. Most recently, PredictWind was updated on November 13, 2026 and Slackwater on November 11, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*