Table of the USDA Plant Hardiness Zones:

zone          minimum temperature

1           less than – 45°C / – 49°F

2           – 45°C up to – 40°C / – 49°F up to – 40°F

3           – 40°C up to – 34°C / – 40°F up to – 29°F

4           – 34°C up to – 29°C / – 29°F up to – 20°F

5           – 29°C up to – 23°C / – 20°F up to – 9°F

6           – 23°C up to – 18°C / – 9°F up to 0°F

7           – 18°C up to – 12°C / 0°F up to +10°F

8           – 12°C up to – 7°C / + 10°F up to + 19°F

9           – 7°C up to 0°C / + 19°F up to + 32°F

10           0°C up to + 5°C / +32°F up to + 41°F

11           + 5°C up to + 10°C / + 41°F up to + 50°F

12           + 10°C up to +15°C / + 50°F up to + 59°F

The temperature for given zone of each species is only for indication and it always depends on specific conditions of your area – the amount and consistency of precipitation in the winter, the course of spring and autumn weather etc.