This week's Tuesday Map illustrates the fragile and spotty nature of Africa’s "Internet Weather" -- or "teledensity" as tracked by Internet monitoring technology.

Researchers at the Abdus Salam International Centre for Theoretical Physics in Trieste, Italy, tracked Internet connectivity at points in more than 40 African countries, whose populations make up more than 80 percent of the continent's inhabitants. Their findings (pdf) are sad, though not surprising: "Africa's network performance is over 10 years behind that of Europe and the U.S. and falling further behind," and among African countries "performances in developing regions are a factor of 5-20 times worse than that in developed regions."

This video maps daily connectivity and explains each dot's meaning (in a funny British accent):

Hat tip: Today's Tuesday Map has been made possible by the PingER (Ping End-to-end Reporting) project of the Internet End-to-end Performance Measurement (IEPM) group at Stanford Linear Accelerator Center (SLAC).