I use QuickWeather and use the Open-Meteo integration. You can even selfhost it for better privacy probably.

Gold cube? You mean the CHEESE?

If you want to continue in the same function you'll need to use async/await. In your case:

async function yourFunctionName(){
    // previous logic
    const myVar = await fetch("myFile.json")
        .then(res => res.json());
    console.log(myVar);
    //rest of code executes...
}

Realize that you have to add async to your function and await to your fetch call. Also take into account that if your function returns anything, it'll now return a Promise instead.