Uh oh, DuckDuckGo has been using Dark Sky for its weather results for the past year [1]. Wonder what they're going to replace it with once the API shuts down?
However, based on Apple's historic decisions and the current market conditions, I won't be surprised if Apple buys DDG before the end of 2021. So maybe DDG will not need to worry about switching from DarkSky.
[1] https://spreadprivacy.com/duckduckgo-weather-results/