I think that Darksky has minutely summary not for all locations. Such forecasts requires local sources. For my location it always return not available.
If you are in a location served by Weather Underground, it won’t be a problem for long. WU does forecasting (which I have been anxiously awaiting since the first PR for support died on the vine) and a new PR will be merged soon that will allow you to use WU for forecasting.
The reason I am so excited about this is that I have a personal weather station that updates to WU so my forecasting will be infinitely more accurate than using DarkSky or Yahoo Weather.
That’s a good news! I’ve founded a weather station next to my work location. So I’ll be ready for the next merging.
Meanwhile I used the lang option but the “summary” is still in english.