The spread of this virus is accelerating, but worsening outbreaks are concentrated in certain parts of the state. To determine where the virus is spreading, we calculated that the rate of new cases in each county, the amount of cases reported at the previous 14 days per 10,000 inhabitants, subsequently mapped that information over time. The animated map shows how — and when — the coronavirus propagate around California from April 1 through July 9.
In early April, the virus was prevalent in Bay Area and Southern California counties, then became more concentrated in Los Angeles and Imperial counties toward the end of the month, spurred by widespread public transmission. As spikes were triggered by large outbreaks at prisons in Kings County and Santa Barbara in May, the virus spread farther into the country.
Back in June the virus obtained a stronger hold in many areas of Southern California and the Central Valley, and in late June and early July the virus was spreading quickly nearly everywhere in the state, with few exceptions.
On April 1, only 12 counties had a rate of more than 2.5 cases per 10,000 residents in the previous 14 days. On June 1 it climbed to 26 counties with an elevated new case speed, and by July 9 nearly all California counties, 53 of 58 counties experienced a brand new instance rate over 2.5.
While the condition has radically increased testing to the coronavirus, that doesn’t fully explain the rising rate of diseases. As testing capacity quickly improved, the positive test rate was on the decrease for months, but it started climbing in June.
The map shows California’s early pre-order arrangement likely spared the state from the first exponential growth seen in places like Italy and New York, but while the Golden State kept the curve under control for many weeks, the trend lines have gotten steeper and worse this season.
Find more data on coronavirus cases, hospitalizations and deaths in the Bay Area and elsewhere in California with our Coronavirus Tracker