---
title: "Seven-day NWS forecast for coordinates"
method: GET
path: "/api/v1/weather/nws/forecast"
tags: ["Environment"]
---

# Seven-day NWS forecast for coordinates

`GET /api/v1/weather/nws/forecast`

Return a seven-day (14-period alternating Day/Night) forecast for the requested coordinates. Sugra chains the two upstream calls (`/points/{lat,lon}` -> `/gridpoints/{wfo}/{x,y}/forecast`) into a single request. Each period includes start/end time, temperature with unit, probability of precipitation, wind speed range and direction, a short forecast phrase and a detailed forecast sentence. US territory only. Attribution: NOAA National Weather Service (api.weather.gov).

## Query parameters

- `lat` number, required — Latitude in decimal degrees, -90 to 90. US territory only.
- `lon` number, required — Longitude in decimal degrees, -180 to 180. US territory only.

## Response `200`

Forecast periods plus gridpoint metadata.

- EnvelopeNwsForecastPayload
  - `data` NwsForecastPayload, required — Forecast response (daily or hourly).
    - `latitude` number, required — Requested latitude echoed back.
    - `longitude` number, required — Requested longitude echoed back.
    - `wfo` string, nullable — Weather forecast office serving this point.
    - `grid_x` integer, nullable — Gridpoint x coordinate.
    - `grid_y` integer, nullable — Gridpoint y coordinate.
    - `city` string, nullable — Nearest NWS-reported city.
    - `state` string, nullable — US state code of the city.
    - `time_zone` string, nullable — IANA time zone identifier.
    - `elevation_m` number, nullable — Gridpoint elevation above mean sea level.
    - `elevation_unit` string, nullable — Short symbol for the elevation unit.
    - `generated_at` string, nullable — Timestamp when NWS rendered the response (ISO 8601).
    - `update_time` string, nullable — Timestamp of the last forecaster update (ISO 8601).
    - `valid_times_interval` string, nullable — ISO 8601 interval over which the forecast is valid.
    - `forecast_generator` string, nullable — NWS generator label: `BaselineForecastGenerator` for daily, `HourlyForecastGenerator` for hourly.
    - `count` integer, required — Number of forecast periods returned.
    - `periods` ModelsNoaaNwsNwsForecastPeriod[], required — Ordered forecast periods.
      - `number` integer, nullable — Period sequence number (1 = nearest period).
      - `name` string, nullable — Period label (e.g. `Tonight`, `Monday`, `Wednesday Night`).
      - `start_time` string, nullable — Period start time (ISO 8601 with offset).
      - `end_time` string, nullable — Period end time (ISO 8601 with offset).
      - `is_daytime` boolean, nullable — True when the period covers daylight hours.
      - `temperature` number, nullable — Forecast temperature for the period.
      - `temperature_unit` string, nullable — `F` (Fahrenheit) or `C` (Celsius).
      - `temperature_trend` string, nullable — Trend label: `rising`, `falling`, or null.
      - `precipitation_probability_percent` number, nullable — Probability of precipitation as a percentage.
      - `wind_speed` string, nullable — Wind speed range string (e.g. `5 to 10 mph`).
      - `wind_direction` string, nullable — Cardinal wind direction (e.g. `NW`).
      - `icon` string, nullable — NWS icon URL (for UI rendering).
      - `short_forecast` string, nullable — Short forecast text (one phrase).
      - `detailed_forecast` string, nullable — Detailed forecast text (one or two sentences).
  - `meta` SugraMeta, required — Metadata attached to every /api/v1/* response envelope.
    - `endpoint` string, required — Requested endpoint path.
    - `data_time` string, required — ISO 8601 UTC timestamp of the source data, not of the request.
    - `response_time` string, required — ISO 8601 UTC timestamp when this response was produced.
    - `provider` string, required — API name and version.
    - `source` string, nullable — Identifier of the primary upstream source used for this response.
    - `attribution` string, nullable — Human-readable attribution mandated by an upstream source (e.g. a securities regulator or self-regulatory organization). Present only on responses whose source requires the owner and source to be clearly identified. Do not remove or alter it when using the response.
    - `fallback_used` boolean, nullable — True when the primary source failed and a fallback produced the data.
    - `fallback_chain` string[], nullable — Ordered list of sources attempted, in the order they were tried.
    - `cached` boolean, nullable — True when this response was served from the internal cache.
    - `stale` boolean, nullable — True when the cached response was returned after the upstream rate-limited or errored. Clients can use this to detect degraded data.

## Other responses

- `401` — Missing or invalid `x-api-key` header. JSON body with a stable `code` distinguishing `missing_api_key` (no header sent) from `invalid_api_key` (header sent, key not accepted); any other 401 source carries the generic `unauthorized` with its detail as `reason`. Plus `hint`. `plan` is always null on 401 - an unauthenticated request has no plan; quota exhaustion is 429, not 401.
- `422` — Validation Error
- `429` — Daily rate limit exceeded. Check `X-RateLimit-Reset` for the next window.
- `503` — Upstream source is temporarily unavailable. Retry after a short delay.

---

[API](https://skmtc.net/sugra/apis/sugra-api.md) · [All operations](https://skmtc.net/sugra/apis/sugra-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/sugra/sugra-api/versions/d3e3d9c28132/schema)