# Chronosync: Circadian Health — Sunlight, sleep, and timing

> Sunlight, sleep, and timing (iPhone/iPad app by JTR Labs LLC.)

- Source: https://appshunter.io/ios/app/chronosync-circadian-health/id6781776422 (this page in markdown: same URL + `.md`)
- Developer: [JTR Labs LLC](https://appshunter.io/developer/1892768253)
- Category: Health & Fitness, Weather
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 15.0 · 8 MB
- Languages: American English
- Released: 2026-07-16
- Data updated: 2026-08-08
- User reviews in markdown: https://appshunter.io/ios/app/chronosync-circadian-health/id6781776422/reviews.md

## What is Chronosync?

Chronosync Plus helps you understand your day through the light around you. Track sunrise, solar noon, sunset, UV context, estimated vitamin D exposure, sleep timing, and evening routines from one private, local-first iPhone app built around circadian awareness.

Features:
• Solar-aware daily dashboard
• Sunrise, solar noon, and sunset alarms
• Estimated vitamin D tracking based on UV, skin type, clothing coverage, and sky conditions
• UVA and UVB context with plain-language explanations
• Sun session timer with IU/min estimates, session summaries, and Live Activities
• Sleep log and chronotype-based timing tools
• Blue-blocking glasses reminders
• Solar flare and space weather context
• Native iOS Shortcuts actions
• Local-first privacy with no Chronosync account required

Subscriptions:
Chronosync Pro Monthly and Chronosync Pro Annual unlock Pro features including timeline, score, night routines, sleep log, vitamin-D estimates, solar activity context, solar alarms, and advanced sun-session tools.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://chronosyncplus.com/privacy

Important: Chronosync Plus is an educational wellness tool. It is not medical advice, not a medical device, and not a substitute for professional care. Vitamin D, UV, burn-time, and circadian outputs are estimates and may be inaccurate or incomplete.

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Chronosync Pro Monthly | $4.99 | per month |
| Chronosync Pro Annual | $49.99 | per year |



## Version history (last 5 releases)

### 1.6 — 2026-08-03

Fixes the Premium upgrade screen so it opens reliably from Settings and keeps its Close and Refresh controls below the Dynamic Island and status bar. Also improves notification routing, Sun Session Live Activity cleanup, launch location loading, onboarding layout, light-mode readability, sleep history, and Shortcuts behavior.

### 1.5 — 2026-07-30

Fixes Sun Session Live Activities so Lock Screen and Dynamic Island timers update continuously and end immediately when a session stops. Improves launch location loading, onboarding and Settings layout, light-mode readability, notification scheduling, sleep history, and Shortcuts behavior.

### 1.4 — 2026-07-27

Fixes native iOS Shortcuts so Blue Phone, Red Phone, Wake, and Sleep apply the correct Chronosync mode on launch. Also improves Night sleep logging for circadian score history.

### 1.3 — 2026-07-26

Improved onboarding spacing, light-mode readability, notification scheduling, sleep logging clarity, sunrise alarm timing, and Vitamin D session controls.

### 1.2 — 2026-07-24

Version 1.2 polishes the Premium experience and keeps the core app easier to explore. Full tabs are no longer locked behind Pro; Premium is now presented clearly in Settings with the upgraded features and capabilities listed. This update also adds a Rate Chronosync Plus section in Settings and includes the latest sun-session, Live Activity, onboarding, notification, and circadian-insight fixes.

## More apps by JTR Labs LLC

- [TaskTimer: Reminders & Alarms](https://appshunter.io/ios/app/tasktimer-reminders-and-alarms/id6762071195)
- [Ice Study: Visual Study Timer](https://appshunter.io/ios/app/ice-study-visual-study-timer/id6762922488)
- [Rice Pop: Visual Study Timer](https://appshunter.io/ios/app/rice-pop-visual-study-timer/id6772216110)
- [Instinct: Dog Enrichment Games](https://appshunter.io/ios/app/instinct-dog-enrichment-games/id6774742651)
- [Air Fryer: Visual Study Timer](https://appshunter.io/ios/app/air-fryer-visual-study-timer/id6776078493)
- [ZenSquish: Stress Relief Toy](https://appshunter.io/ios/app/zensquish-stress-relief-toy/id6777472312)

All apps by JTR Labs LLC: https://appshunter.io/developer/1892768253

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*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 2026-08-08.*