# Vrain by Watec vs Biển Vô Cực

The clearest difference is iOS requirement: Biển Vô Cực at 13.0 against Vrain by Watec's 15.6. On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Vrain by Watec ships an update every 9 days, Biển Vô Cực every 5 days. The most recent releases landed on October 29, 2026 and October 18, 2026 respectively.

## The numbers

| Metric | Vrain by Watec | Biển Vô Cực |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/bien-vo-cuc/id6745475821/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | 20.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 9 days | **Every 5 days** |
| Monetization | Free | Free |
| Size | 54 MB | 25 MB |
| Requires iOS | 15.6 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [RESOURCE WATER CONSULTANT AND DEVELOPMENT TECHNICAL JOINT STOCK COMPANY](https://appshunter.io/developer/1559532093) | [Dinh Tuan](https://appshunter.io/developer/1577522054) |

## What reviewers say

### Vrain by Watec

[App page](https://appshunter.io/ios/app/vrain-by-watec/id1241610832)

This application provides real-time rainfall data and alerts for provinces across Vietnam. Users can view rainfall at various measurement stations nationwide or within a specific province. Receive notifications when rainfall exceeds predefined thresholds.

**Highlights:** View rainfall at provincial stations, View nationwide rainfall data, Receive rainfall alerts, Monitor rainfall thresholds

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Biển Vô Cực

[App page](https://appshunter.io/ios/app/bien-vo-cuc/id6745475821)

This app provides tide and lunar calendar information for fishermen, seafarers, and ocean enthusiasts. It serves as a lookup tool for marine data, helping users plan their activities related to the sea.

**Highlights:** Tide calendar lookup, Lunar calendar information, Marine data for fishermen, Tool for seafarers, App for ocean nature lovers

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Vrain by Watec free?

Vrain by Watec is free to download, with no in-app purchases.

### Is Biển Vô Cực free?

Biển Vô Cực is free to download, with no in-app purchases.

### Do Vrain by Watec or Biển Vô Cực have ads?

Neither Vrain by Watec nor Biển Vô Cực shows ads.

### Which is updated more often, Vrain by Watec or Biển Vô Cực?

Vrain by Watec ships an update every 9 days, and Biển Vô Cực every 5 days. Most recently, Vrain by Watec was updated on October 29, 2026 and Biển Vô Cực on October 18, 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.*