Open Moon Calendar logoOpen Moon Calendar

Privacy Policy

Short version: your moon calculations stay on your device. No accounts, no data selling. We use Google Analytics (GA4) to understand aggregate usage (e.g. which pages are popular) — see section 2 below.

Last updated: September 11, 2026

1. Data we do NOT collect

  • No accounts, names, emails, or passwords are required or collected.
  • No precise GPS coordinates are sent to our servers by this site.
  • No fingerprinting or advertising trackers are bundled with the core experience. The only third-party measurement is Google Analytics, described in section 2.
  • Feedback you submit in the Contact & Feedback form is stored only in your browser's local storage unless you choose to email it to us.

2. Analytics (Google Analytics 4)

We use Google Analytics 4 (measurement ID G-R2P391S058), provided by Google LLC, to understand aggregate usage — e.g. which pages are visited most and roughly which countries visitors come from — so we can improve the site. Google Analytics may collect your device and browser information, approximate location (derived from IP address), pages visited, and interactions via JavaScript and cookies (such as _ga).

  • Data is processed by Google on our behalf under Google's terms and Privacy Policy.
  • We do not combine Analytics data with account identities (there are no accounts) and never sell personal data.
  • You can opt out anytime: use Google's opt-out browser add-on, enable "Do Not Track" / Global Privacy Control compatible blocking, or block third-party cookies and googletagmanager.com / google-analytics.com in your browser or ad blocker.

3. Data stored on your device

To make the app fast and offline-capable, your browser may store:

  • Theme preference (openmoon_theme) — light or dark mode.
  • Observer location — city name and coordinates you select, so moonrise/moonset times persist between visits.
  • Language preference — your chosen interface language.
  • Feedback drafts (openmoon_feedback_submissions) — only if you use the feedback form.

You can clear all of this at any time by clearing your browser's site storage. The site keeps working without it.

4. Location permission

If you tap "Use Current Location", your browser's Geolocation API resolves your position on your device. Those coordinates are used only to compute local moon/sun times and are never uploaded to our servers. Denying permission simply falls back to a default city — you can always pick a city manually.

5. Cookies

Beyond the strictly-necessary localStorage described above, Google Analytics (see section 2) sets its own cookies (such as _ga) to distinguish visits and measure aggregate usage. We do not set advertising cookies ourselves. If we introduce third-party advertising (e.g. Google AdSense) in the future, that provider may set its own cookies subject to its own policy — this page will be updated before that happens. You can delete or block cookies in your browser settings; the core calendar keeps working without them.

6. Contacting us

If you email us via the Contact page, we receive only what you send (your address, subject, message) and use it solely to reply. We never sell or share personal data.

7. Children

The site is a general-audience educational tool with no accounts or user-generated public content, and is suitable for all ages. We do not knowingly collect data from children.

8. Changes to this policy

If this policy changes materially, we will update the "Last updated" date above. Continued use of the site after changes constitutes acceptance.

9. Questions

Questions about privacy? Reach us via the Contact page. Related: Terms & Conditions.