Tucson UArizona, USA Live Cam

The University of Arizona campus fills the foreground and the Santa Catalina Mountains close the view, at Tucson. The webcam carries a line of weather data along the bottom of the picture.

Dendrochronology was invented on this campus. An astronomer studying sunspots began counting tree rings here in the 1900s to get at a record of past climate, and the laboratory he founded still dates timbers for archaeologists around the world.

Those mountains climb from desert at 800 metres to conifer forest above 2,700, a change equivalent to driving to Canada. There is a ski area at the top, the southernmost in the United States, an hour from a city where summer afternoons pass forty degrees.