Guides
A moon phase app for iPhone: how to choose one
People install a moon app for one reason: a two second look, once a day. That habit decides whether the app is still there a month later. It is also the only useful way to choose one.
Facts checked 2026-08
So you know where this page comes from: I make Plenilune, the illustrated lunar almanac this site belongs to. Before I drew the first line of it, I read more than 13,000 App Store reviews of moon apps. It took me a month, and it taught me more than any feature list would have. What follows is a checklist. I name no winner, because the right app depends on what you came for.
What a moon app is for
Four uses come back in the reviews, again and again. Knowing tonight's phase without opening anything. Knowing the rise and set times, because that is what decides if you will see the Moon at all. Knowing the date of the next full moon, for a walk, a photograph, a sowing. And, for a smaller group, reading the sky properly: distance, libration, eclipses visible from where you live.
Everything else serves one of those four, or none. 3D globes, augmented reality compass, zodiac wheel. Decide which one is yours before you look at a single screenshot, and the choice takes five minutes.
Five things to check before you install
- A widget that stays up to date. The app you keep is the one you stop opening, because the widget already answered. In the reviews of every moon app, the first complaint is a widget that stopped updating. Usually because it depends on a server, or on a subscription check made over the network.
- Times computed where you are. The phase is the same for the whole Earth. Rise, set and eclipse visibility are not: they depend on your latitude and longitude, to the minute. An app that shows a rise time without ever asking where you are is giving you another city's times.
- Offline, and no account. The Moon's motion can be computed years ahead. Nothing in there needs a network or a sign-up. If an app asks for your email before it shows you the Moon, that is a commercial choice.
- The price, before you tap. The model is written on the App Store page, in the In App Purchases section. What generates the most one star reviews in this category is the free install that shows nothing until you subscribe.
- Astronomy or astrology. Both are fine, they are simply not the same app. Many listings blur the line: an ephemeris on the screenshots, a horoscope inside. The reviews are clearer than the listing about this.
What an app should be able to tell you, right now
Here is what a good moon app shows the moment you open it, computed for this instant. Compare: the app you install should give the same values, and should show them without you having to look for them.
Free, paid, subscription
The phase of the Moon is public knowledge. What you pay for is the drawing, the accuracy of the times, and the absence of advertising. Five models cover almost the whole category, and each one has its own flaw.
| Model | What you usually get | What to look at |
|---|---|---|
| Free, funded by ads | The full app, with banners or interstitials | The advertising identifier follows you out of the app, and the widget often carries ads too |
| Free, with a paid unlock | A usable daily glance, the rest behind one purchase | How much of the daily glance is free before the unlock |
| Subscription | Everything, for as long as you keep paying | You rent a calculation that never changes; check the price after the introductory period |
| One time purchase | Everything, once | Rare in this category, and worth looking for if renewals annoy you |
| Free trial, then subscription | A few days of everything | Trials that start at install and renew silently; the date of the first charge |
For Plenilune, I may as well write it here: free, with an optional Premium at 9.99 euros a year or 24.99 euros once, for life. The eurozone prices are the reference, then the App Store applies its own tier by country. Widgets, today's phase, moonrise and moonset are in the free version.
The traps
- Astrology dressed as astronomy. A phase disc on the screenshots, a personalised prediction inside.
- A widget that needs a server. It works for a week, then it shows yesterday's Moon. No phase calculation needs the network.
- Free that shows nothing. Look at what the free app displays before you decide.
- Times computed for a default city. Ask for the rise time where you live and compare it with another source. One hour off means the app does not take your position into account.
- A countdown on the subscription screen. There is no urgency in a moon app, and the urgency on screen is a sales technique.
What Plenilune does
Plenilune is an almanac. The Moon is never a photograph in it: the app engraves the disc from the ephemerides of the moment, so the phase, the libration and the angle in your sky are the ones of that moment, redrawn every night. Underneath, I wrote the engine after Meeus, for phase, position, rise, set, and eclipse visibility from where you stand; tests compare it against a table of real full moons. Everything is computed on the device. No account, no advertising, no advertising identifier. iPhone and iPad, iOS 17 and later, in six languages.
It does not do everything. No augmented reality compass, no 3D globe of the craters, no horoscope, no ritual reminders. If you photograph the sky and you need azimuth, altitude and eclipse maps, a more instrumental app will serve you better. If you want one beautiful, exact look a day, and the twelve named moons with their stories, this is the one I drew.
Questions
- Is there a moon phase app without a subscription?
- Yes, in two forms. Some apps are free and funded by advertising. Others, mine included, are free with an optional one time purchase that unlocks everything for life. On the App Store page, the In App Purchases section gives the exact model before you install anything.
- Do moon apps work offline?
- The good ones do. The Moon's motion is predictable for centuries: a phase, a rise time, an eclipse date can all be computed on the device. An app that needs a connection to give you tonight's phase is fetching from a server an answer it did not need.
- Does a moon phase app need my location?
- For the phase, no: it is the same everywhere on Earth at a given instant. For moonrise, moonset and whether an eclipse is visible where you stand, yes, and to the minute. A well made app asks for location for those, and does without it for the rest.
- Is Plenilune available on Android?
- No. It is an iPhone and iPad app, iOS 17 and later. I wrote it with Apple's own drawing and widget tools, which is part of why the engravings and the lock screen widgets look the way they do.
- What is the difference between a moon phase app and an astrology app?
- A moon phase app tells you what the sky is doing: the phase, the times, the dates, the names inherited from farmers' almanacs. An astrology app tells you what it means for you. Plenilune does the first: it tells what people have read in the sky, not what the Moon has in store for you.