I bet you do have the skills to write it up in Rules using the HTTP binding and/or the sendHttpXRequest Actions though. I’ve done so in the past for more complicated APIs than that: Honeywell Home API with openHAB using just rules.
I don’t use that anymore because the reauthentication never quite worked right but you don’t need any of that Oauth2 and authentication token request token stuff. You just need to make some calls and parse out the data.
If it’s as you describe you might be able to do most of the work just with the HTTP binding. However, if you need to manipulate the JSON entries to get meaningful data back (like was required with the NOAA work I did years ago which I can’t find now but the problem was to calculate the total precipitation one had to process an unknown and ever changing number of entries, not a fixed number (like one entry per hour)) you might need to process the JSON in a rule.
I’d give it a try, you might get much farther than you think.