Free sun & moon API

JSON API

Request today's times for a city, or pass ?date=YYYY-MM-DD for any day. The response is CORS-enabled, so you can call it straight from the browser.

GET https://sunandmoon.app/api/sun/london
GET https://sunandmoon.app/api/sun/tokyo?date=2026-12-25

Example response (trimmed):

{
  "city": { "name": "London", "country": "United Kingdom",
            "slug": "london", "timezone": "Europe/London",
            "lat": 51.5074, "lon": -0.1278 },
  "date": "2026-07-12",
  "sun": {
    "sunrise": { "iso": "2026-07-12T03:57:00.000Z", "local": "04:57" },
    "sunset":  { "iso": "2026-07-12T20:14:00.000Z", "local": "21:14" },
    "dayLengthMinutes": 977,
    "goldenHour": { "evening": { "start": {...}, "end": {...} } },
    "twilight": { "civilDawn": {...}, "civilDusk": {...} }
  },
  "moon": { "phaseName": "Waning Crescent", "illumination": 0.05,
            "moonrise": {...}, "moonset": {...} },
  "attribution": "https://sunandmoon.app"
}

Every time is returned both as a UTC iso instant and a localstring in the city's own time zone. Events that do not occur (polar day or night) are null. City slugs match the site's URLs, e.g. /api/sun/london, /api/sun/new-york.

Embeddable widget

Drop a compact live card into any page with an iframe. It shows today's sunrise, sunset, day length, golden hour and moon for the city, and links back here.

<iframe src="https://sunandmoon.app/embed/london"
  width="420" height="220" style="border:0"
  title="London sun times"></iframe>

Try it: /embed/london, /embed/tokyo.

Calendar feed (ICS)

Subscribe to a city's sunrise and sunset in any calendar app and today's light shows up next to your meetings. It is a standard iCalendar (.ics) subscription: no account, no key, and it rolls forward on its own, so you add it once and forget it.

# subscribe in a calendar app
webcal://sunandmoon.app/api/ics/london

# or fetch the file over https
https://sunandmoon.app/api/ics/tokyo?events=sunrise,sunset,goldenhour

What the feed contains

Each request returns the next 90 days for that city as a text/calendardocument. Every event is a zero-length marker at the exact instant of the event, titled with the time and the city, and linked back to that city's page. The calendar advertises a one-day refresh interval (REFRESH-INTERVAL:P1D), which is what makes it keep itself current: your calendar app re-fetches the URL and picks up the next horizon of days. Events that do not occur, such as sunset during polar summer, are simply absent rather than faked.

Options

Adding it to your calendar

In Google Calendar, open Other calendars, choose From URL and paste the https:// form. In Apple Calendar, use File then New Calendar Subscription, or simply click a webcal:// link on an Apple device. In Outlook, use Add calendar then Subscribe from web. Each app decides how often it re-fetches; most honour the one-day interval, some are lazier.

Examples: /api/ics/london (sunrise and sunset), /api/ics/tokyo?events=sunrise,sunset,goldenhour (the photographer feed). Free to use and to link to, in your own projects or your own newsletter. An attribution link back is appreciated.

Field reference

Every time field is an object with two members: iso, a UTC instant in ISO 8601, and local, an HH:MM string already converted to the city's own time zone. A field is null when the event does not occur that day, which happens inside the polar circles.

The moon phase value

moon.phase is the position in the synodic month, from 0 to 1: 0 is new moon, 0.25 first quarter, 0.5 full moon, 0.75 last quarter. Naming a phase means putting boundaries on that number, and there is no universal convention. These are ours: a narrow band of half a day either side of each principal phase, and wide bands for the four intermediate names, so a moon called full really looks full.

The API computes the moon for the moment of the request; the HTML pages compute it for local midnight at the start of the city's day. Close to a boundary the two can therefore differ by one name and by about a percentage point of illumination. Full reasoning on methodology.

Errors and edge cases

An invalid ?date= is not an error: anything that is not YYYY-MM-DDis ignored and today in the city's time zone is used instead. Above the Arctic Circle and below the Antarctic Circle there are days with no sunrise or no sunset at all; those fields come back null rather than as a made-up time, and dayLengthMinutes is then 1440 during midnight sun and 0 during polar night. Try /api/sun/tromso?date=2026-06-21 and /api/sun/tromso?date=2026-12-21.

Public dataset

Beyond the per-request API there is a single file with the shape of the whole year per city: total daylight hours, the longest and shortest day, the earliest and latest sunrise and sunset (which are not the solstices, and that is the interesting part), the fastest day-length change, and the counts of midnight sun, polar night and never-fully-dark days.

https://sunandmoon.app/data/daylight-year.json
https://sunandmoon.app/data/daylight-year.csv

Licensed CC BY 4.0: use it anywhere, including commercially, with attribution to sunandmoon.app. Licence text.

Code examples

curl:

curl -s https://sunandmoon.app/api/sun/london | jq '.sun.sunset.local'

JavaScript, straight from the browser:

const r = await fetch("https://sunandmoon.app/api/sun/london");
const d = await r.json();
console.log(d.city.name + " sunset: " + d.sun.sunset.local);

Python:

import urllib.request, json

url = "https://sunandmoon.app/api/sun/london"
with urllib.request.urlopen(url) as r:
    d = json.load(r)

print(d["city"]["name"], d["sun"]["sunset"]["local"])

iOS Shortcuts: add a Get Contents of URL action pointed at https://sunandmoon.app/api/sun/london, then a Get Dictionary Value action with the key sun.sunset.local, then Show Result. No key and no account, so it works from a personal automation.

Licence and attribution

The API, the widget, the calendar feed and the dataset are free to use, including commercially, under CC BY 4.0. There is no key and no rate limit for reasonable use. In exchange we ask for one thing: a visible link back to sunandmoon.app. The embed widget keeps that link itself, so if you use the widget you are already done. If you call the API directly, please put the link somewhere a reader can see it. The attribution field in every response carries the URL so you can render it automatically.

Changelog

There is no version in the URL and no breaking change is planned. Fields may be added; existing fields will not be removed or renamed without a note here first.

Frequently asked questions

More