City of Azusa, CA
This utility did not file a reliability report
City of Azusa is one of only 12 utilities nationally that filed no outage-frequency or outage-length figures in the most recent federal reliability filing. That is a gap in the reporting, not evidence the grid in California is reliable or unreliable - there is simply nothing filed to measure it against. Check the California state figure below instead, or ask City of Azusa directly for its own outage history before deciding on a generator. Who owns a utility says a lot about its likely record - see co-ops vs city-owned utilities.
Where this number comes from
These figures come from EIA Form 861, the reliability report a municipally-owned utility like City of Azusa files with federal regulators every year - averaged across the whole territory, not any one address or storm. Want the California average instead of just this one utility? California's statewide record is here. One big storm can move a single year a lot; major event days explains how.