The API was inaccessible from 23:30 on 12 April 2014 to 03:00 on 13 April 2014, a period of 3.5 hours. The cause for this downtime was that our service provider’s datacenter experienced a power outage, causing all of our servers hosted with them to become inaccessible. As soon as power was restored, our services automatically resumed. Several minor issues persisted throughout the day of 13 April 2014, including utilizing slightly stale weather data (causing minor accuracy loss) and the unavailability of historical weather data, causing historical requests before 1 Jan 2012 to return invalid results.
While this exact issue was beyond our control, there are steps we can take to mitigate similar issues in the future, such as utilizing redundant data centers. While the API was not originally built to support this sort of redundancy, we have been slowly working towards this goal over the past several months and will continue to do so during this year, in order to provide a more reliable service.