Sun & Moon API

Q: Can I query a date in the past?

Yes, any date: pass date=YYYY-MM-DD.

Sunrise, sunset, civil dawn and dusk, day length, moon phase, illumination, moonrise and moonset for any place and date, up to 7 days per call.

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50 free requests, no credit card.

GET/api/v1/astronomyMonterey, California (local time)

{
    "lat": 36.605,
    "lon": -121.888,
    "timezone": "America/Los_Angeles",
    "date": "2026-10-18",
    "days": 2,
    "data": [
        {
            "date": "2026-10-18",
            "sun": {
                "sunrise": "07:18",
                "sunset": "18:28",
                "dawn": "06:52",
                "dusk": "18:54",
                "day_length": "11:10"
            },
            "moon": {
                "phase": "waxing_crescent",
                "illumination_pct": 48.9,
                "age_days": 7.3,
                "moonrise": "16:29",
                "moonset": "01:36"
            }
        }
    ],
    "port": {
        "name": "Monterey Ca",
        "slug": "monterey-ca",
        "country": "United States"
    }
}

Days per call1 to 7

Any datepast or future

Time zonelocal with port, UTC with lat/lon

Computationastronomical, no model

Request

GEThttps://tidesatlas.com/api/v1/astronomy

Parameter	Type	Description
`lat, lon`	float	Coordinates (decimal degrees). Times are returned in UTC.
`port`	string	Instead of lat/lon: a station slug. Times are returned in the station's local time zone.
`date`	YYYY-MM-DD	First day. Default: today.
`days`	int	1 to 7. Default 1.
`X-API-Key`	header	Your API key (or `?api_key=` in the query string).

Code examples

curl "https://tidesatlas.com/api/v1/astronomy?port=monterey-ca&days=1" \
  -H "X-API-Key: YOUR_KEY"

const params = new URLSearchParams({ port: 'monterey-ca', days: 1 });
const res = await fetch(`https://tidesatlas.com/api/v1/astronomy?${params}`, {
  headers: { 'X-API-Key': 'YOUR_KEY' }
});
const data = await res.json();

import requests

r = requests.get(
    "https://tidesatlas.com/api/v1/astronomy",
    params={"port": "monterey-ca", "days": 1},
    headers={"X-API-Key": "YOUR_KEY"},
    timeout=30,
)
data = r.json()

$ch = curl_init('https://tidesatlas.com/api/v1/astronomy?port=monterey-ca&days=1');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ['X-API-Key: YOUR_KEY'],
]);
$data = json_decode(curl_exec($ch), true);

Response

Real response for Monterey, California (local time), 18 October 2026 (arrays shortened).

{
    "lat": 36.605,
    "lon": -121.888,
    "timezone": "America/Los_Angeles",
    "date": "2026-10-18",
    "days": 2,
    "data": [
        {
            "date": "2026-10-18",
            "sun": {
                "sunrise": "07:18",
                "sunset": "18:28",
                "dawn": "06:52",
                "dusk": "18:54",
                "day_length": "11:10"
            },
            "moon": {
                "phase": "waxing_crescent",
                "illumination_pct": 48.9,
                "age_days": 7.3,
                "moonrise": "16:29",
                "moonset": "01:36"
            }
        }
    ],
    "port": {
        "name": "Monterey Ca",
        "slug": "monterey-ca",
        "country": "United States"
    }
}

Field	Meaning
`data[].sun.sunrise / sunset`	Sunrise and sunset, HH:MM
`data[].sun.dawn / dusk`	Civil twilight start and end
`data[].sun.day_length`	Day length, HH:MM
`data[].moon.phase`	`new_moon`, `waxing_crescent`, `first_quarter`, `waxing_gibbous`, `full_moon`, …
`data[].moon.illumination_pct / age_days`	Illuminated fraction (%) and days since new moon
`data[].moon.moonrise / moonset`	Moonrise and moonset, HH:MM

Data sources

Computed on our servers with standard astronomical algorithms (solar position and lunar ephemeris). No external service, so responses are fast and available for any date.

Good to know

With lat/lon the times are UTC: for places far from Greenwich, sunset can fall on the next UTC day. Use port to get local times.
Twilight is civil twilight (sun 6° below the horizon).

FAQ

Can I query a date in the past?

Yes, any date: pass date=YYYY-MM-DD.

Why do fishermen and photographers use it?

Moon phase drives tidal range (spring tides near new and full moon); dawn, dusk and moonrise plan the light.

Which plans include it?

The Complete pack, which also includes tides, and the weather-only pack. New accounts get 50 free requests; see the docs for current prices.