There are 7 climate zones on-line: each will tell you which parts of the area covered correspond to each respective USDA zone. Each has a zone and temperature key to help you. For example, if you see a plant listed as "Zone 7", and you live in New York (Zone 6), you know that the plant won't be hardy outside.

USA: Continent	*	USA: Alaska and Hawaii
USA: East	*	USA: West
Europe	*	China
Australia
For your information, this is a scale which will allow you to convert °Fahrenheit into °Celcius and vice versa.