There have been so many outages this is now the third reported instance on the system status page…
When the weather service is down, the Apple Weather app (available on iPhone, iPad and Mac) and widgets will show loading states or report an error message like ‘no weather data’. The outages are seemingly intermittent; it’s up for a few minutes, and then it is down again.
As a stock default app on the iPhone, Weather is used by millions of Apple customers every single day. Apple acquired Dark Sky in March 2020 to help overhaul the system app with a first-party data backend and new user-facing features like next-hour precipitation alerts and weather maps.