# Sun Day Tracker vs Rays

The clearest difference is in-app purchases: Sun Day Tracker at none against Rays's 2. Sun Day Tracker also leads on review sentiment (83% vs 75%) and ratings volume (26 vs 7). Rays's advantage is update cadence (every 5 days vs monthly) and iOS requirement (15.1 vs 17.0). On price, rating, ads and device support there is nothing between them.

Both are free to download. Rays sells 2 in-app purchases, starting at $4.99 per month. Sun Day Tracker asks for nothing beyond the download.

Sun Day Tracker holds the better App Store score, 4.6 against 4.4. Both are backed by a comparable volume of ratings — 26 and 7 respectively. Written reviews point the same way: 83% of Sun Day Tracker's written reviews are positive against 75% of Rays's.

Sun Day Tracker ships an update monthly, Rays every 5 days. The most recent releases landed on September 19, 2026 and September 7, 2026 respectively.

## The numbers

| Metric | Sun Day Tracker | Rays |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.6 (26 ratings)](https://appshunter.io/ios/app/sun-day-tracker/id6748545544/reviews)** | [4.4 (7 ratings)](https://appshunter.io/ios/app/rays-auto-vitamin-d-tracking/id6752499967/reviews) |
| Number of ratings | **26** | 7 |
| Positive reviews | **83.3% of reviews** | 75.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Monthly | **Every 5 days** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 1 MB | 58 MB |
| Requires iOS | 17.0 | **15.1** |
| Devices | iPhone | **iPhone, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [permissionless tech, llc](https://appshunter.io/developer/1824145893) | [Rays Health Technologies LLC](https://appshunter.io/developer/1829292925) |

## What reviewers say

### Sun Day Tracker

[App page](https://appshunter.io/ios/app/sun-day-tracker/id6748545544)

Monitor your daily vitamin D absorption from sunlight exposure. This straightforward application helps you keep track of your sun-related vitamin D intake.

**Highlights:** Track daily vitamin D intake, Sunlight exposure monitoring, Simple interface, Daily tracking

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

**In-app purchases:** none


### Rays

[App page](https://appshunter.io/ios/app/rays-auto-vitamin-d-tracking/id6752499967)

Automatically tracks your body's vitamin D synthesis from sun exposure. Get personalized recommendations for optimal timing and duration to maintain energy, mood, and skin health year-round without manual logging.

**Highlights:** Automatic vitamin D synthesis tracking, Personalized health intelligence, Smart sun exposure recommendations, Progress tracking and health insights, Apple Health integration, Minimal battery usage

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Rays - Auto Vitamin D Tracker | $4.99 | per month |
| Rays - Auto Vitamin D Tracker | $19.99 | per year |


## Frequently asked questions

### Is Sun Day Tracker free?

Sun Day Tracker is free to download, with no in-app purchases.

### Is Rays free?

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

### Which has better reviews, Sun Day Tracker or Rays?

Sun Day Tracker is rated higher. Sun Day Tracker averages 4.6 out of 5 from 26 ratings, while Rays averages 4.4 from 7 ratings.

### Do Sun Day Tracker or Rays have ads?

Neither Sun Day Tracker nor Rays shows ads.

### Which is updated more often, Sun Day Tracker or Rays?

Sun Day Tracker ships an update monthly, and Rays every 5 days. Most recently, Sun Day Tracker was updated on September 19, 2026 and Rays on September 7, 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.*