The fork
https://github.com/gerjomarty/MMM-DarkSkyForecast

uses the openweather API. Works like charm.

updateInterval: 15 * 60 * 1000, //every 15 minutes or whatever you choose

that’s the original ^ and I updated the 15 to 60.

I guess I don’t understand what each number represents. Milliseconds, Seconds, Minutes? >

Hi @cotxwx - I think the updateInterval in the original is currently set to 15 minutes. The time will be based in milliseconds, so reading it right-to-left that gives you

1000 (milliseconds per second) x 60 (seconds per minute) x 15 = a 15 minute interval

which I think ends up being clearer than just giving a sort of anonymous/unit-free total (e.g. 900000 or something like that)

hope this helps anyway

		{
			module: "MMM-DarkSkyForecast",
			//header: "Weather",
			position: "top_right",
			classes: "default everyone",
			disabled: false,
			config: {
			    apikey: "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX",
			    latitude: "43.XXXXXX",
			    longitude: "-79.XXXXXX",      
			    updateInterval: "30", //this is in minutes, so every 30 minutes
			    iconset: "3c",
			    showCurrentConditions: true,
			    showExtraCurrentConditions: false,
			    showSummary: true,
			    showForecastTableColumnHeaderIcons: false,
			    concise: true,
			    forecastLayout: "table", //other option is "table"
 		 	}
		},

scheduleUpdate: function() {
        setInterval(() => {
            this.getNOAA();
        }, this.config.updateInterval);
        this.getNOAA(this.config.initialLoadDelay);
    },

this code shows that the API calls really are determined by updateInterval (as you thought).
Here something comes into play that I stumbled upon.

If you have several entities of the mirror open, let’s say you are also using a browser e.g. to develop, the main.js (and hence the setInterval function) will be started a second, third, fourth etc. time.
In that case you would have SEVERAL interval cycles asking for an API call every x minutes.
That can blow the API call ratio.
Don’t know if that’s the case with you.

That’s why I try to keep an API call cycle always inside the node_helper.js and have it start only once in my modules.

"Your trial account allows up to 1,000 free calls per day to evaluate the Dark Sky API. If you would like > to make more than 1,000 calls per day, simply enter billing information to upgrade to a full account. "

So you need to stay below 1,000 calls/day.
I have seen that MMM-NOAA uses a new API provider, weatherbit.

You might want to do an update.

DarkySky have changed their API billing for new subscribers and I believe there are no free plans available anymore.
Did you subscribe just recently?
What is your tier/plan?
Do you know which interval you’d need to get free API calls?

Before you throw money at them, there are many free weather services out there and someone may have already reprogrammed your module to use another (free) API provider.