Sun API Parameters

Sunrise & Sunset | Sunshine Duration | Relative Sunshine Duration | UV Index | Solar Azimuth Angle | Solar Elevation Angle | Day & Night | Solar Eclipse

Sunrise & Sunset

These parameters return the times of sunrise and sunset in UTC at a given location.

sunrise:<unit>
sunset:<unit>

Sunrise and sunset times are available in the following units: sql, dn, ux


sql will return a time stamp according to the ISO-86011 format (YYYY-MM-DDThh:mm:ssZ).

dn refers to the date number. The date number represents the whole and fractional number of days from 1-Jan-0000 to a specific date and is equivalent to the serial date number used in Matlab.

ux refers to the Unix timestamp. It gives the total number of elapsed seconds since 00:00:00 UTC on the 1st of January 1970.

Note: Some special cases may occur, which give rise to the following outputs (no date/time outputs):

-777: The sun is not visible

-888: The sun is always visible

Note: When these variables are queried for a specific time, the last sunrise before the query’s time will be returned. The sunset that will be returned will be the one following the sunrise mentioned before. In general, the returned sunset will always be after the returned sunrise and the returned sunrise will be the last one before the query time.

Example:

  • Shows the sunrise and sunset time over a period of one week:
    https://api.meteomatics.com/2024-07-23T00:00:00Z--2024-07-30T00:00:00Z:P1D/sunrise:sql,sunset:sql/47.423336,9.377225/csv
    validdate;sunrise:sql;sunset:sql
    2020-04-15T22:00:00Z;2020-04-15T04:33:00Z;2020-04-15T18:10:00Z
    2020-04-16T22:00:00Z;2020-04-16T04:31:00Z;2020-04-16T18:12:00Z
    2020-04-17T22:00:00Z;2020-04-17T04:29:00Z;2020-04-17T18:13:00Z
    2020-04-18T22:00:00Z;2020-04-18T04:27:00Z;2020-04-18T18:14:00Z
    2020-04-19T22:00:00Z;2020-04-19T04:25:00Z;2020-04-19T18:16:00Z
    2020-04-20T22:00:00Z;2020-04-20T04:24:00Z;2020-04-20T18:17:00Z
    2020-04-21T22:00:00Z;2020-04-21T04:22:00Z;2020-04-21T18:19:00Z
    2020-04-22T22:00:00Z;2020-04-22T04:20:00Z;2020-04-22T18:20:00Z

Accumulated Sunshine duration

Gives the amount of time the sun was shining within the requested interval.

sunshine_duration_<interval>:<unit>

Available intervals: 1h, 3h, 6h, 12h, 24h

Available Units: h, min

Examples:

Relative sunshine duration

The duration of sunshine divided by the amount of time the sun was above the horizon at the queried coordinate and time.

sunshine_duration_24h:p

Examples:

UV Index

The UV Index is computed based on model outputs and downscaled with 90m-resolution topography data. Instantaneous values as well as maxima within certain time periods can be queried.
uv:idx
uv_max_<interval>:idx

Available intervals: 1h, 2h, 3h, 6h, 12h, 24h

Example:

Solar Azimuth Angle

The solar azimuth angle defines the sun's relative direction along the local horizon.

sun_azimuth:d
Example:
  • The solar azimuth angle for London on Feb 11th, 2021:
    validdate;sun_azimuth:d
    2021-02-10T00:30:00Z;4.7
    2021-02-10T01:00:00Z;16.6
    2021-02-10T01:30:00Z;27.8
    2021-02-10T02:00:00Z;38.2
    2021-02-10T02:30:00Z;47.6
    2021-02-10T03:00:00Z;56.2
    2021-02-10T03:30:00Z;63.9
    2021-02-10T04:00:00Z;71.1
    2021-02-10T04:30:00Z;77.7
    2021-02-10T05:00:00Z;83.9
    2021-02-10T05:30:00Z;89.9
    ...
    2021-02-10T18:30:00Z;263.8
    2021-02-10T19:00:00Z;269.6
    2021-02-10T19:30:00Z;275.6
    2021-02-10T20:00:00Z;281.8
    2021-02-10T20:30:00Z;288.4
    2021-02-10T21:00:00Z;295.4
    2021-02-10T21:30:00Z;303.1
    2021-02-10T22:00:00Z;311.6
    2021-02-10T22:30:00Z;321.0
    2021-02-10T23:00:00Z;331.3
    2021-02-10T23:30:00Z;342.4
    2021-02-11T00:00:00Z;352.7
    Current situation:
    https://api.meteomatics.com/2024-07-22T00:30:00Z--2024-07-23T00:00:00Z:PT30M/sun_azimuth:d/51.508021,-0.129410/html

Solar Elevation Angle

The solar elevation angle (angle between the sun and the horizon) gives the position of the sun above the horizon.
sun_elevation:d
Example:

Day & Night

These two parameters tell you whether the sun is below or above the horizon.

0: sun below the horizon, 1: sun above the horizon

is_day:idx

0: sun above the horizon, 1: sun below the horizon

is_night:idx

Example:

Solar Eclipse

Variable referring to the obscuration of the Sun's disk caused by the Moon. It depends on the position of the Sun and the Moon.

solar_eclipse:p 

Example:

Example:
  • Solar Eclipse in North America on the 8th of April, 2024 plotted with MetX.
    Solar eclipse metx

Footnotes

  1. ISO-8601 date format: https://www.iso.org/standard/40874.html, http://en.wikipedia.org/wiki/ISO_8601