# Sauna Assistant vs RayDay

The clearest difference is price: RayDay at Free against Sauna Assistant's $19.99. Sauna Assistant's advantage is in-app purchases (none vs 3). On update cadence, ads, device support and iOS requirement there is nothing between them.

RayDay is free to download; Sauna Assistant costs $19.99 up front. RayDay sells 3 in-app purchases, starting at $4.99 per 7 days. Sauna Assistant asks for nothing beyond the download.

Both ship on a similar rhythm, roughly every 3 weeks. The most recent releases landed on October 28, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Sauna Assistant | RayDay |
| --- | --- | --- |
| Price | $19.99 | **Free** |
| Rating | — | **[3.0 (2 ratings)](https://appshunter.io/ios/app/rayday-vitamin-d-tracker/id6761286896/reviews)** |
| Number of ratings | — | **2** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | Every 3 weeks |
| Monetization | — | Freemium |
| Size | 390 MB | 26 MB |
| Requires iOS | 17.0 | 17.0 |
| Devices | iPhone, Apple Watch | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [DAINIUS SERPLIS](https://appshunter.io/developer/1801676293) | [Jakub Laszczyk](https://appshunter.io/developer/568719342) |

## What reviewers say

### Sauna Assistant

[App page](https://appshunter.io/ios/app/sauna-assistant-ritual-timer/id6743150443)

**Features:** macOS Compatibility, Apple Watch app

**In-app purchases:** none


### RayDay

[App page](https://appshunter.io/ios/app/rayday-vitamin-d-tracker/id6761286896)

This app helps you understand your daily window for natural Vitamin D production. It calculates optimal sun exposure times based on your location and skin type, providing forecasts and real-time atmospheric data.

**Highlights:** D-Window Calculator, Live Solar Path animation, 7-Day D-Window Forecast, Skin Type Personalization, Smart Notifications, Real-time Atmospheric Data, Home Screen Widget

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| RayDay Weekly | $4.99 | per 7 days |
| RayDay Yearly | $24.99 | per year |
| Early Supporter Yearly | $24.99 | per year |


## Frequently asked questions

### Is Sauna Assistant free?

Sauna Assistant costs $19.99, with no in-app purchases.

### Is RayDay free?

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

### Do Sauna Assistant or RayDay have ads?

Neither Sauna Assistant nor RayDay shows ads.

### Which is updated more often, Sauna Assistant or RayDay?

Sauna Assistant ships an update every 3 weeks, and RayDay every 3 weeks. Most recently, Sauna Assistant was updated on October 28, 2026 and RayDay on October 31, 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.*