# metno.forecast

**stable** **Standard**

Current conditions and next-hour outlook (MET Norway locationforecast compact).

`GET /v1/metno/forecast`

## What you get

One Metno record in Onekey's unified shape, in `data`. If the record does not exist you get a `404 not_found` and are not charged.

## What it costs

- **Standard · 1 credit** for a fresh fetch, charged only when it succeeds.
- **Free when served from cache (0.2 credit for a cached response over 100 KB).**
- **Free** if the request is invalid (never charged) or the source fails or reports not found (refunded).

## Parameters

| Name | Type | Required | Default | What it is | Constraints |
| --- | --- | --- | --- | --- | --- |
| `lat` | string | yes | (required) | Latitude (max 4 decimals) | max 8 chars; must match `-?\d{1,2}(?:\.\d{1,4})?`; trimmed |
| `lon` | string | yes | (required) | Longitude (max 4 decimals) | max 9 chars; must match `-?\d{1,3}(?:\.\d{1,4})?`; trimmed |

## Request

```bash
curl "https://api.onekey.dev/v1/metno/forecast?lat=60.1&lon=9.6" \
  -H "x-api-key: YOUR_API_KEY"
```

```python
import requests

res = requests.get(
    "https://api.onekey.dev/v1/metno/forecast",
    params={"lat": "60.1", "lon": "9.6"},
    headers={"x-api-key": "YOUR_API_KEY"},
)
body = res.json()

if body["success"]:
    print(body["data"])
else:
    print(body["error"]["code"], body["error"]["message"])
```

```javascript
const params = new URLSearchParams({ lat: "60.1", lon: "9.6" });
const res = await fetch(`https://api.onekey.dev/v1/metno/forecast?${params}`, {
  headers: { "x-api-key": "YOUR_API_KEY" },
});
const body = await res.json();

if (body.success) console.log(body.data);
else console.error(body.error.code, body.error.message);
```

## Recorded response

A real Metno response, recorded and returned in Onekey's shape. Fields the platform does not provide are `null`.

```json
{
  "success": true,
  "data": {
    "place": {
      "elevationM": 508
    },
    "entity": {
      "createdAt": "2026-09-28T19:31:45Z",
      "date": "2026-09-28T20:00:00Z",
      "category": "fair_night"
    },
    "ext": {
      "temperatureC": 7.9,
      "humidityPct": 71.3,
      "windSpeedMs": 2,
      "pressureHpa": 1021,
      "cloudCoverPct": 22.8,
      "precipitationNextHourMm": 0
    }
  },
  "metadata": {
    "platform": "metno",
    "endpoint": "forecast",
    "cached": false,
    "stale": false,
    "age_s": 0,
    "fetched_at": "2026-01-01T12:00:00+00:00",
    "credits_charged": 1,
    "request_id": "7f3a9c2e5b1d4c8fa2e6d0b9c4f18e37"
  },
  "error": null
}
```

## Field mapping

How this endpoint's source fields become Onekey's [unified schema](https://onekey.dev/docs/schema.md). Fields the source lacks come back as `null`.

| Source path | Onekey field | Transform |
| --- | --- | --- |
| `geometry.coordinates.2` | `place.elevationM` | `toNumber` |
| `properties.meta.updated_at` | `entity.createdAt` | `toIsoDate` |
| `properties.timeseries.0.time` | `entity.date` | `toIsoDate` |
| `properties.timeseries.0.data.instant.details.air_temperature` | `ext.temperatureC` | `toNumber` |
| `properties.timeseries.0.data.instant.details.relative_humidity` | `ext.humidityPct` | `toNumber` |
| `properties.timeseries.0.data.instant.details.wind_speed` | `ext.windSpeedMs` | `toNumber` |
| `properties.timeseries.0.data.instant.details.air_pressure_at_sea_level` | `ext.pressureHpa` | `toNumber` |
| `properties.timeseries.0.data.instant.details.cloud_area_fraction` | `ext.cloudCoverPct` | `toNumber` |
| `properties.timeseries.0.data.next_1_hours.summary.symbol_code` | `entity.category` | - |
| `properties.timeseries.0.data.next_1_hours.details.precipitation_amount` | `ext.precipitationNextHourMm` | `toNumber` |

## Caching and freshness

- Fresh for about 30 seconds. Repeat calls in that window are served from cache and are free.
- Between 30 seconds and 5 minutes the cached copy is still served instantly and marked `stale: true` while Onekey refreshes it in the background.
- If the source is down when a refresh is needed, the last copy can be served for up to 1 hour more (marked stale).
- A "not found" is remembered for 1 minute and is free.
- The cache is shared across all customers, which is what keeps repeat calls cheap.

## What can go wrong

| Status | Code | What to do |
| --- | --- | --- |
| 401 | `unauthorized` | Check the `x-api-key` header. |
| 402 | `insufficient_credits` | [Add credits](https://onekey.dev/pricing); your balance must cover the price. |
| 404 | `not_found` | That record does not exist. Free; do not retry. |
| 422 | `invalid_params` | Fix the parameters using the table above. Free. |
| 429 | `rate_limited` | Wait `Retry-After` seconds, then retry. |
| 502 | `upstream_error` | The source failed. Refunded; retry with backoff. |

See [Errors](https://onekey.dev/docs/errors.md) for the full list and retry guidance.

Status: stable (verified against the live source).