Terms of Service
Effective July 6, 2026.
1. What DarkSky Index is
DarkSky Index provides stargazing forecast pages for hospitality properties. You add your property, and we publish a page that shows guests a night-by-night view of expected sky darkness, moon phase, and Milky Way visibility for your location.
2. Your account
You need an account to use DarkSky Index. Give us a working email address, keep your password to yourself, and tell us if you think someone else has access to your account. You are responsible for what happens under your account.
3. Billing
DarkSky Index costs $3.85/mo per property or $25.80/yr per property (save 44% yearly), after a 14-day free trial. No credit card is required to start the trial. You can cancel anytime through the billing portal in your dashboard, and your subscription ends at the close of the period you already paid for. Payments are processed by Polar, our Merchant of Record: Polar sells you the subscription and pays us, handles your payment details and any applicable sales tax, and appears as the merchant on your card statement. We never see or store your card details.
4. What our forecasts are (and are not)
Our forecasts are astronomical estimates: moon phase, sky darkness, and Milky Way visibility, computed from the position of your property. Where we show a Bortle sky class, it is labeled "(estimated)" because it is derived from data, not measured on site. We do not forecast weather. Clouds, haze, and local conditions can hide the sky on any night, and we make no guarantee about what your guests will actually see. We say the same thing to your guests on your page.
5. Acceptable use
Use DarkSky Index only for lawful purposes and only for properties you are authorized to represent. Do not enter false property information, attempt to break or overload the service, or resell access to it.
6. Your content and ours
You own the content you add about your property (its name, description, links, and images). You give us permission to show that content on your forecast page and in the service. DarkSky Index owns the service itself: the software, the forecasts, and the design.
7. Ending the relationship
You can stop using DarkSky Index and cancel your subscription at any time. We may suspend or close accounts that violate these terms or stop paying, after which your public page is automatically paused.
8. Liability
The service is provided as-is. To the extent the law allows, our total liability to you is limited to the fees you have paid us. We are not liable for bookings, cancellations, or guest experiences that follow from the forecasts we publish, because the sky is not ours to promise.
9. Changes to these terms
We may update these terms as the product evolves. When we do, we will update the effective date at the top of this page. Continuing to use DarkSky Index after a change means you accept the new terms.
10. Contact
Questions about these terms? Email support@darkskyindex.com.
See also our Privacy Policy, or go back to the homepage.