Apple claimed to have integrated Dark Sky's technologies into their Weather app but clearly haven't. I've relied on Dark Sky's rain notifications for years and they've always been remarkably accurate (UK here), but the stock Weather app sends maybe one notification per 100 rains. So far this year, since Apple turned off Dark Sky, I haven't received a single rain notification and consequently I've been absolutely drenched on several dog walks.
“What’s this weeks weather going to be” I’d use another source.
“Will I get rained in if I leave the house now, or should I wait 30 mins?” I’d use dark sky
I’ve switched to Apple Weather which has been a reasonable replacement but I don’t like it as much