How to Get Swedish Weather Data via API

Published March 12, 2026 · 5 min read

SMHI (Swedish Meteorological and Hydrological Institute) provides free weather data through their open API. But working with it directly means dealing with coordinate-based lookups, cryptic parameter codes, and deeply nested JSON structures.

This guide shows you how to get Swedish weather data the easy way — with a single API call that returns clean, developer-friendly JSON.

The Problem with SMHI's Raw API

SMHI's meteorological forecast API (opendata-download-metfcst) requires you to:

1. Know exact GPS coordinates — there's no city name lookup. You need to convert "Stockholm" to lat=59.33&lon=18.07 yourself.
2. Decode parameter codes — temperature is t, wind speed is ws, precipitation is pmean. There are 30+ parameters with non-obvious names.
3. Parse nested time series — the response is a flat array of timesteps, each containing an array of parameter objects. No summary, no daily aggregation.

Raw SMHI API call

curl "https://opendata-download-metfcst.smhi.se/api/category/pmp3g/version/2/geotype/point/lon/18.07/lat/59.33/data.json"

{
  "approvedTime": "2026-03-12T14:00:00Z",
  "referenceTime": "2026-03-12T12:00:00Z",
  "geometry": { "type": "Point", "coordinates": [[18.07, 59.33]] },
  "timeSeries": [
    {
      "validTime": "2026-03-12T15:00:00Z",
      "parameters": [
        { "name": "t", "levelType": "hl", "level": 2, "unit": "Cel", "values": [4.2] },
        { "name": "ws", "levelType": "hl", "level": 10, "unit": "m/s", "values": [3.1] },
        { "name": "pmean", "levelType": "hl", "level": 0, "unit": "kg/m2/h", "values": [0.0] },
        { "name": "Wsymb2", "levelType": "hl", "level": 0, "unit": "category", "values": [3] }
        // ... 20+ more parameters
      ]
    }
    // ... 100+ more timesteps
  ]
}

To get "What's the temperature in Stockholm?" you need to: find the right coordinates → make the request → loop through timeSeries → find the parameter where name === "t" → extract values[0]. That's a lot of boilerplate for a simple question.

The Apiverket Way

// 1. Geocode city name somehow
const lat = 59.33, lon = 18.07;

// 2. Fetch raw SMHI data
const res = await fetch(
  `https://opendata-download-metfcst
  .smhi.se/api/category/pmp3g
  /version/2/geotype/point
  /lon/${lon}/lat/${lat}
  /data.json`
);

// 3. Parse cryptic response
const data = await res.json();
const now = data.timeSeries[0];
const temp = now.parameters
  .find(p => p.name === "t")
  .values[0];

const res = await fetch(
  "https://apiverket.se/v1/weather" +
  "/Stockholm/forecast",
  {
    headers: {
      Authorization:
        "Bearer sk_live_YOUR_KEY"
    }
  }
);

const { data } = await res.json();
// data.current.temperature = 4.2
// data.current.description = "Partly cloudy"
// data.forecast = [{day, high, low, ...}]

What You Get

The /v1/weather/{city}/forecast endpoint returns:

• Current conditions — temperature, wind, humidity, description, weather symbol
• 10-day forecast — daily high/low, precipitation probability, wind, description
• Observations — latest measured values from the nearest SMHI station
• Weather alerts — active SMHI warnings for the area

Example response

{
  "meta": {
    "request_id": "req_abc123",
    "api_version": "2026-02-15",
    "mode": "live",
    "sources": [{
      "agency": "smhi",
      "fetched_at": "2026-03-12T14:30:00Z",
      "cache_ttl": 600,
      "freshness": "live"
    }]
  },
  "data": {
    "city": "Stockholm",
    "coordinates": { "lat": 59.33, "lon": 18.07 },
    "current": {
      "temperature": 4.2,
      "feels_like": 1.8,
      "humidity": 72,
      "wind_speed": 3.1,
      "wind_direction": "SW",
      "description": "Partly cloudy",
      "symbol": 3
    },
    "forecast": [
      {
        "date": "2026-03-12",
        "high": 6.1,
        "low": 1.3,
        "precipitation_mm": 0.0,
        "description": "Partly cloudy"
      }
      // ... 9 more days
    ]
  }
}

Available Weather Endpoints

Try It Now

You can test with the sandbox key immediately — no signup needed:

curl -H "Authorization: Bearer sk_test_demo123" \
  https://apiverket.se/v1/weather/Stockholm/forecast

Test mode returns realistic sandbox data. When you're ready for live data, sign up for free and get a sk_live_ key with 200 requests per day.