Sunrise Sunset Grounding Data

Overview

Sunrise Sunset works by calculating the sunrise and sunset times based on the location and date provided. It returns the sunrise and sunset times in a structured format.

The tool

Once your client is connected to the VerveContext server, this appears in its tool list as SunriseSunsetGroundingData. It is read-only and open-world — it fetches and never mutates anything on your side — so most clients call it without asking you to confirm.

Tool call

{
  "name": "SunriseSunsetGroundingData",
  "arguments": {
    "lat": "36.72016",
    "lon": "-4.42034"
  }
}

You do not name the tool yourself; the model picks it. Asking about 36.72016 in the terms this source covers is enough for it to reach for SunriseSunsetGroundingData on its own — naming it explicitly also works, and is the way to force the call.

Connecting

One server URL covers every source in the catalog, including this one. Authorization is OAuth: the client opens a browser once, and there is no key to paste into a config file.

{
  "mcpServers": {
    "vervecontext": {
      "url": "https://api.vervecontext.com/v1/mcp"
    }
  }
}

Per-client setup — Claude, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made. Premium arguments are accepted on every plan but only take effect on plans that include them.

Argument	Type	Description
`lat`Required	number	The latitude of the location range -90–90
`lon`Required	number	The longitude of the location range -180–180
`date`OptionalPremium	string	The date for which you want to get the sunrise and sunset times (e.g., MM-DD-YYYY : 01-01-2022) date

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client reads fields without parsing prose. status is "ok" and error is null on success; a null field means the value was not available for that input, not that the call failed.

Result

{
  "status": "ok",
  "error": null,
  "data": {
    "solarNoon": "2025-12-16T12:14:40.51Z",
    "sunrise": "2025-12-16T07:24:56.165Z",
    "sunset": "2025-12-16T17:04:24.854Z",
    "sunriseEnd": "2025-12-16T07:27:58.828Z",
    "sunsetStart": "2025-12-16T17:01:22.192Z",
    "dawn": "2025-12-16T06:56:02.774Z",
    "dusk": "2025-12-16T17:33:18.245Z",
    "nauticalDawn": "2025-12-16T06:23:38.134Z",
    "nauticalDusk": "2025-12-16T18:05:42.886Z",
    "nightEnd": "2025-12-16T05:52:07.048Z",
    "night": "2025-12-16T18:37:13.971Z",
    "goldenHourEnd": "2025-12-16T08:05:08.406Z",
    "goldenHour": "2025-12-16T16:24:12.613Z"
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`solarNoon`Premium	string	`2025-12-16T12:14:40.51Z`	Solar noon time
`sunrise`	string	`2025-12-16T07:24:56.165Z`	Sunrise time in ISO 8601 format
`sunset`	string	`2025-12-16T17:04:24.854Z`	Sunset time in ISO 8601 format
`sunriseEnd`	string	`2025-12-16T07:27:58.828Z`	Moment the sun's disc has fully cleared the horizon, in UTC
`sunsetStart`	string	`2025-12-16T17:01:22.192Z`	Moment the sun's disc first touches the horizon at sunset, in UTC
`dawn`	string	`2025-12-16T06:56:02.774Z`	Start of civil twilight, when the sun is 6 degrees below the horizon
`dusk`	string	`2025-12-16T17:33:18.245Z`	End of civil twilight, when the sun drops 6 degrees below the horizon
`nauticalDawn`	string	`2025-12-16T06:23:38.134Z`	Start of nautical twilight, when the sun is 12 degrees below the horizon
`nauticalDusk`	string	`2025-12-16T18:05:42.886Z`	End of nautical twilight, when the sun drops 12 degrees below the horizon
`nightEnd`	string	`2025-12-16T05:52:07.048Z`	End of astronomical night, when the sun rises above 18 degrees below the horizon
`night`	string	`2025-12-16T18:37:13.971Z`	Start of astronomical night, when the sun drops 18 degrees below the horizon
`goldenHourEnd`	string	`2025-12-16T08:05:08.406Z`	End of the morning golden hour, when soft low-angle light gives way to daylight
`goldenHour`	string	`2025-12-16T16:24:12.613Z`	Start of the evening golden hour, when the light turns soft and low-angle

Why ground on it

A model can produce something that looks like this answer from its training data, and be confidently out of date or simply wrong. This source returns the current value in a shape you can check, which is the difference between an answer you can cite and one you have to hedge.

Point an evaluation at sunrise: it is the field most worth pinning a claim to, and it is either present and current or absent — never plausibly invented.

Failure modes

Errors come back as tool errors carrying a sentence the model can act on, not a bare status code. Error handling covers the full list.

Status	What it means
`400` / `422`	The arguments did not validate. The message names the offending one.
`401`	The OAuth session is invalid or expired — reconnect the server.
`403`	Blocked by a key restriction or an IP allow-list. Never a bad identity.
`404`	This source is not part of VerveContext. Check the catalog.
`429`	Out of credits, or a brief rate limit. The message tells them apart.

A call costs 1 credit each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Use cases

Photography: Use the Sunrise Sunset API to get sunrise and sunset times for photography. Use the data to plan shoots, capture golden hours, and optimize lighting
Outdoor Activities: Plan outdoor activities by using the Sunrise Sunset API to get sunrise and sunset times. Use the data to schedule events, organize trips, and optimize experiences
Gardening: Get sunrise and sunset times by using the Sunrise Sunset API for gardening. Use the data to plan planting, schedule harvests, and optimize crop growth
Weather App: Use the Sunrise Sunset API to get sunrise and sunset times for a weather app. Use the data to display weather information, provide forecasts, and offer alerts

Other ways to use Sunrise Sunset Grounding Data

Set up Sunrise Sunset Grounding Data on VerveContext, or reach the same source a different way. Your VerveContext account and credits work on all of them — one key, one balance.

Call it as a REST APIOne HTTPS endpoint and an x-api-key header, with SDKs for Node, Python and .NET.APIVerve →Reference →

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.VerveKit →Reference →

Use it in Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheets →Reference →