Canada
Canada Zone Map: https://planthardiness.gc.ca/?m=1
In addition to the average minimum temperatures of the coldest month, other factors built into the Canadian system include:
- the number of frost-free days,
- amount of June to November rainfall,
- snow depth,
- maximum wind speed
- and other factors.
The ratings run from cold to hot, zone 1 to zone 9.
UK
UK Zones: https://www.rhs.org.uk/advice/rhs-hardiness-rating
If you weren’t confused enough already, the UK system runs from hot to cold (H1-H7), meaning the hottest locations are in zone H1 and the coldest locations are in zone H7. This runs counter to the US and Canadian systems where higher zone numbers indicate hotter temperatures.
They’ve also used zone H1 to indicate 3 different types of INDOOR (mostly greenhouse) climates:
- H1a is warmer than 15C (>59F), indicating a TROPICAL heated glasshouse environment (needs to be grown as a house plant or under glass all year round). Equivalent to USDA zone 13.
- H1b is 10 to 15C (50 to 59F), indicating a SUBTROPICAL heated glasshouse environment (can be grown outdoors in summer in sunny and sheltered locations but generally performs best as a house plant or under glass all year round). Equivalent to USDA zone 12.
- H1c is 5 to 10C (41 to 50F), indicating a WARM TEMPERATE heated glasshouse environment (can be grown outdoors in summer throughout most of the UK while daytime temperatures are high enough to promote growth). Equivalent to USDA zone 11.
H2 (1 to 5C, 34 to 41F) is their first zone describing year-round outdoor climates in a few, rare frost-free UK areas.
Also, instead of the long-term (monthly average) extreme minimum temperature used for the USDA zones, the UK temperature ranges are intended to document absolute minimum winter temperatures.
Australia
Australian Bureau of Meteorology classification is based on temperature, humidity, and rainfall patterns: http://www.bom.gov.au/info/climate-zone/
New Zealand
New Zealand’s national climate classification (NIWA) is used for horticulture and agriculture: https://niwa.co.nz/climate
World Zones
https://evergreenbotany.com/blogs/news/plant-growing-zones
- The map’s climate/hardiness zones were modeled using NAPPFAST (2012) climate data.
- The map uses the WGS84 global coordinate reference system.
- The work was done by the USDA APHIS PPQ CPHST research center in Raleigh.
- A specific contact scientist (D. Borchert) was responsible for the dataset.
Acronym Explanation
1. NAPPFAST (2012)
NAPPFAST = The North Carolina State University APHIS Plant Pest Forecasting System
- Developed with USDA to model pest spread, climate suitability, hardiness, and phenology.
- Used to generate climate and hardiness maps for agriculture and forestry.
So “NAPPFAST 2012” means the map was generated using 2012 climate modeling data from this system.
2. WGS–GCS–1984
This refers to the coordinate system used in the map.
- WGS = World Geodetic System
- GCS = Geographic Coordinate System
- 1984 = the 1984 revision (WGS84)
WGS84 is the global standard coordinate reference system used by:
- GPS
- Google Maps
- All modern GIS systems
This just tells you the map is aligned with global geospatial standards.
3. USDA–APHIS–PPQ–CPHST
This is a long chain of subdivisions inside the U.S. Department of Agriculture. The research-science division of USDA Plant Protection & Quarantine created or validated this map.
- USDA: U.S. Department of Agriculture
- APHIS: Animal and Plant Health Inspection Service (the agency responsible for protecting U.S. agriculture from pests and diseases)
- PPQ: Plant Protection and Quarantine (the branch that monitors plant pests, imports, invasive species, and biological risks)
- CPHST: Center for Plant Health Science and Technology (the research and scientific analysis division of PPQ)
4. Raleigh, N
The headquarters for CPHST and many federal APHIS analytical operations.
5. Contact: D. Borchert
A USDA scientist or analyst responsible for the map or data model.
6. August 31, 2012
That’s simply the publication or data generation date.