OpenWeather One Call API vs Visual Crossing Weather API

OpenWeather One Call API

1,000 free calls a day, then $0.0015 a call, or $0.001 on the agent lane. The main API takes the key only as the appid query parameter.

Visual Crossing Weather API

History from 1970, current conditions and a 15-day forecast from one endpoint. Key only in the query string on the REST API.

OpenWeather One Call API

1. Sign up on the agent lane with POST https://agents.openweathermap.org/v1/accounts and keep the data key. It's shown once
2. Check GET https://data.openweathermap.org/account/balance for credit. No data response carries a cost or balance
3. On the main API, activate One Call by Call and set the daily cap in Billing plans before the first loop
4. Pass units=metric. The default is Kelvin
5. Use exclude=minutely,alerts on 3.0, or the 4.0 timeline step you need, to shrink responses

Visual Crossing Weather API

1. Always pass include= and elements=. A bare call returns days, hours and current for every element and burns records
2. Count records before a backfill. Hourly data is 24 records a day, so a year for one place is 8,760
3. Pass unitGroup=metric. The default is US units
4. Use the MCP server with X-VC-API-Key rather than pasting the key into a URL
5. Keep to one request at a time on Free and Professional. A second concurrent job returns 429