According to Apple System Status, all iCloud services are currently down for some users. The outage has been going on for a little over an hour now with no indication of when the service might be restored.
iCloud services appear to be the only services affected by the outage, which again, doesn’t affect all users. Other online services such as FaceTime, iMessage, Siri, and the App Stores are currently working just fine.
Update: System Status page now says all services have been restored.
Apple doesn’t give details on how many users are experiencing issues. Depending on your location, iCloud services may or may not work for you.
On a personal note, the confirmation of this outage finally explains why I had issues syncing contacts and calendars since last night, despite no warning being given on the Status page. My issues seem to have been resolved earlier today before there was any sort of indication on the System Status page though.
If you’re having iCloud issues, please share your location in the comments section below. If the outage is specific to some locations, your comment might help pinpoint where exactly.