If you have access to an Apple developer account I would use the [WeatherKit REST API]. It's very similar to the Dark Sky API. (Presumably designed by the same devs). I'm going to ask one of my friends for an API key for their unused free quota.
OpenWeather's [One Call API] is almost a drop-in replacement for the DarkSky API. There are a few minor differences.
[Open-Meteo] is another really good API. Unfortunately it doesn't have the "minutely" forecast data, which I find really useful. (Is it going to start raining in the next few minutes? When will it stop?)
[WeatherKit REST API]: https://developer.apple.com/documentation/weatherkitrestapi
[One Call API]: https://openweathermap.org/darksky-openweather-3
[Open-Meteo]: https://open-meteo.com/