The temperature dividing line between rain and snow usually disappears off the North America weather maps in late June. It usually reappears sometime in late August or early September.

Although the map played a role in loosening Britain’s imperial grip on North America, its original purpose was just the opposite. John Mitchell was born in 1711 to a family of relatively wealthy ...

To create the map, the researchers amassed over 2,000 stress orientations taken across North America, of which 300 are brand new. These measurements were taken from boreholes—long, narrow shafts ...