Open-Meteo API

What it covers

Weather forecast, historical, marine, air-quality, and geocoding APIs with an accessible public tier. The profile stays deliberately concise: use the linked official reference for endpoint schemas and current commercial terms.

Integration notes

Authenticate exactly as the provider documents, keep credentials out of client bundles, and retain upstream request identifiers when available. Pagination, retries, caching, and webhook verification should be implemented per product rather than inferred from another API.

Key endpoints

Endpoint	Description
GET /v1/forecast	Weather forecast (16 days)
GET /v1/archive	Historical weather (ERA5)
GET /v1/air-quality	Air quality forecast
GET /v1/geocoding	Geocoding search
GET /v1/elevation	Elevation data
GET /v1/marine	Marine weather

Decision notes

Best suited to weather prototypes and multi-location forecast requests. Before production, verify attribution and license requirements vary by dataset. commercial use should use the appropriate customer plan. Mutable limits, prices, and versions were checked on 2026-09-13 and should be rechecked at purchase or deployment time.

Python example: weather forecast (no auth)

import httpx
from datetime import date

BASE = "https://api.open-meteo.com/v1"

def forecast(lat: float, lon: float, days: int = 3) -> list[dict]:
    """Get daily forecast. No API key needed."""
    resp = httpx.get(
        f"{BASE}/forecast",
        params={
            "latitude": lat,
            "longitude": lon,
            "daily": "temperature_2m_max,temperature_2m_min,precipitation_sum",
            "forecast_days": days,
            "timezone": "auto",
        },
        timeout=30,
    )
    resp.raise_for_status()
    d = resp.json()["daily"]
    return [
        {
            "date": date.fromisoformat(d["time"][i]),
            "tmax": d["temperature_2m_max"][i],
            "tmin": d["temperature_2m_min"][i],
            "precip_mm": d["precipitation_sum"][i],
        }
        for i in range(len(d["time"]))
    ]

# Seoul
for day in forecast(37.57, 126.98):
    print(day["date"], f"{day['tmin']}~{day['tmax']}C", f"{day['precip_mm']}mm")

Notes:

• Completely free, no API key, generous limits (10000 calls/day)
• Pick variables explicitly via daily / hourly params — the API returns only what you ask
• timezone=auto localizes times; otherwise UTC
• Commercial use is allowed on the free tier within limits; check terms for high volume