USDA climates

As hardiness zone precisely, USDA Plant Hardiness Zones (, hardiness zones'), refers to a climate classification of areas based on the average lowest annual temperature, which the US Department of Agriculture US Department of Agriculture (USDA) has issued.

construction

The zones range from 1 (from −60  ° F , approx. -51.1  ° C ) for polar regions to 13 (up to 70 ° F, approx. 21 ° C) for the tropics , in steps of 10 ° F ( ≈5.5 ° C). The zones can be divided into half steps a and b , each comprising 5 ° F (≈ 2.8 ° C) .

They are an international standard for assessing the winter hardiness of plants. Furthermore, there is a list of indicator plants , which is divided into zones in which these plants can barely survive.

The map for the USA was first issued in 1990. It was based on an averaging period 1974–1986. In order to do justice to global warming , this map was recreated in 2012 and related to the 30-year period 1976-2005. The individual zones shifted to the north within a few hundred kilometers, and in one place the zoning changed by an average of about a 5 ° F half-zone.

Zoning

USDA Plant Hardiness Zone Map (USA)

USDA zones Zone from ° C up to ° C to ° F 1a −51.1 ° C −48.3 ° C −55 ° F 1b −48.3 ° C −45.6 ° C −50 ° F 2a −45.5 ° C −42.8 ° C −45 ° F 2 B −42.7 ° C −40.0 ° C −40 ° F 3a −39.9 ° C −37.3 ° C −35 ° F 3b −37.2 ° C −34.5 ° C −30 ° F 4a −34.4 ° C −31.7 ° C −25 ° F 4b −31.6 ° C −28.9 ° C −20 ° F 5a −28.8 ° C −26.2 ° C −15 ° F 5b −26.1 ° C −23.4 ° C −10 ° F 6a −23.3 ° C −20.5 ° C −5 ° F 6b −20.4 ° C −17.8 ° C 0 ° F 7a −17.7 ° C −15.0 ° C +5 ° F 7b −14.9 ° C −12.3 ° C +10 ° F

USDA zones Zone from ° C up to ° C to ° F 8a −12.2 ° C −9.5 ° C +15 ° F 8b −9.4 ° C −6.7 ° C +20 ° F 9a −6.6 ° C −3.9 ° C +25 ° F 9b −3.8 ° C −1.2 ° C +30 ° F 10a −1.1 ° C +1.6 ° C +35 ° F 10b +1.7 ° C +4.4 ° C +40 ° F 11a +4.5 ° C +7.2 ° C +45 ° F 11b +7.2 ° C +10.0 ° C +50 ° F 12a +10.0 ° C +12.8 ° C +55 ° F 12b +12.8 ° C +15.6 ° C +60 ° F 13a +15.6 ° C +18.3 ° C +65 ° F 13b +18.3 ° C +21.1 ° C +70 ° F

Regional

Zones in Europe

The flatlands of Germany, Austria and Switzerland are in zones 6–7, the Alpine region in zones 5–6, with the high Alps in zones 4–5. Isolated areas with a mild climate such as the Rhineland , coastal regions of Lower Saxony and Schleswig-Holstein due to the Gulf Stream , as well as Bremen and Hamburg , or areas around Lake Geneva and Lake Constance can belong to zones 8 a to 9 a, the island of Heligoland to zone 8 b be assigned. With the global warming is an extensive shift in the individual zones implies, in particular since 2015 partly more than one zone.

Web links

Commons : Hardiness zones  - collection of images, videos and audio files

• USDA Plant Hardiness Zone Map ; USDA Plant Hardiness Zone Map , both usna.usda.gov (English, theory and map of the USA)
• USDA zones / overview for Europe , tropenland.at
• Winter hardiness in Germany and neighboring countries / explanations and map with half-zones , garten-pur.de

Individual evidence

1. ↑ New USDA Plant Hardiness Zone Map for gardeners shows a warming climate. Jeff Masters, in Weater Underground , wunderground.com, February 1, 2012.
2. ↑ https://www.dwd.de/DE/klimaumwelt/klimaatlas/klimaatlas_node.html?selectedSektorId=2