Luckily, Dashboard widgets are just editable html and javascript files, so I rewrote a portion of Apple's weather widget to use the DarkSky API instead. Since the entire point of this project was to support a legacy feature (the Dashboard), I really wanted it to work on the full gamut of OS X 10.4 Tiger – 10.14 Mojave.
My modified version worked fine on 10.9 and above, but on 10.4 – 10.8, users reported being unable to retrieve any weather data. After some back and forth of looking at logs, I found the problem—old versions of OS X didn't support the modern iteration of HTTPS required by DarkSky. I couldn't fix this, because DarkSky doesn't offer their API via HTTP.
Was this really necessary? Weather forecasts are public information, so what level of safety is provided by HTTPS to the point where it should be not just a default, but the only option for developers?
(Luckily, I had the chance to rectify this when Apple bought DarkSky and forced me to change APIs. I'm now using Weatherbit, which offers HTTP. I would have preferred to use HERE, but like DarkSky, they're HTTPS-only.)
https://forums.macrumors.com/threads/i-fixed-apples-broken-w...