Climate Zones

Climate Zones

Bureau of Meteorology – Climate Classes

Providing a gardening climate map is not easy. There are many different approaches by the experts who compile the data, and then interpret it. Here’s an overview of the Australian climate zones, with detailed resources for reference and comparison with other countries.

To know your local climate zone, the best advice is to simply go to your local nursery and ask a horticulturist. Also ask if there are specific factors you should be aware of for your locality.


Why know your Climate Zone?

Plants require the right temperatures to flourish successfully. This means knowing whether plants:

  • need/enjoy cold temperatures (eg tulips)
  • need/enjoy cool temperatures (eg apples)
  • need/enjoy warm or even hot weather (eg mangos)
  • tolerate hot weather that’s humid (bromeliads) or dry (teucrium)
  • can tolerate frost (armeria) or not (bananas)

And do they need winter rain or summer rain?


See below for ‘Practical Information’ to understand how knowing your climate zone relates to buying climbing beans, as an example.

Don’t get overwhelmed by information – you don’t actually need to know a huge amount of detail regarding your climate zone classification – just what to look for when buying or ordering plants and seeds eg. your zone is classed as Tropical or Temperate or Mediterranean etc. The classification will help you to know when to plant.


The Frost factor

Planting is generally carried out in spring or autumn (particularly vegetables which are classified as ‘warm’ or ‘cool’ season crops). To take this in account, the temperate zone -which has warm summers and cool winters – can be divided further into ‘cool temperate’ – subject to frosts – and ‘warm temperate’ which is frost-free.

The timing of first and last frosts will determine when it is safe to plant. This is why you will read on seed packets “Sow once last frost has passed”. This ‘last’ frost can vary from year to year and location to location – even within the same climate zone.

Climate temperature affects soil temperature, resulting in plants not being able to take up moisture if the soil is frozen. Sensitive new shoots can also be damaged as the water within their cells freeze. Plants can often be started off within greenhouses or mini-greenhouses, on window sills and in other warm dry positions. Later seedlings can be potted up and moved to ‘harden off’ outside.

In tropical areas factors other than temperature may limit the suitability of some crops in particular seasons – rain for instance. Humidity is a factor when considering what and when to plant.


Micro-climates

Within all climate zones are micro-climates that can alter the ability to grow various plants. Microclimates can be hills that protect again prevailing winds. You can create your own microclimate too – such as putting up a piece of lattice to buffer the wind so you can grow wind-sensitive plants.


How to determine your climate zone

  • Have a look at the maps provided here and see where you live and look at the corresponding information.
  • The best advice is to simply go to your local nursery and ask a horticulturist.
  • Seed and plant catalogues are also good resources for information.

Garden diary

If you are keen, try keeping a garden diary for 12 months and record maximum and minimum temperatures, and rainfall. You don’t have to record every day but keeping your own records would give you accurate information. Also list when you plant what, and your successes and failures. Don’t forget to include other information such as watering and fertilising.


Climate Zone Maps and Interpretation

The Bureau of Meteorology is an excellent resource for data.  Areas are divided into climatic zones to address the broad conditions for various locations. These are based on minimum and maximum temperatures as well as rainfall.


Here are other climate maps used by Better Homes and Gardens, Gardening Australia and Garden Express (a mail order plant business) – after looking at various climate maps, you will notice similarities and differences.

 

 


Practical information

Here are examples of how information is presented by various companies that supply beans – used an an example is Climbing Bean ‘Blue Lake’:-

 

Beans_EdenSeeds

Beans_EdenSeeds


Guide to Climate Zones

The following information is a general guide only:

COLD OR COOL TEMPERATE

All of Tasmania and all of Southern Victoria, south of and including the foothills of the Great Dividing Range, extending west across the state from Bendigo into SE Australia.

The cold zone follows the Great Dividing Range through NSW into Southern Queensland as far North as Dalby. Spring in cold areas usually refers to October and November.

Tasmania has a cool temperate climate with four distinct seasons. Summer lasts from December to February when the average maximum sea temperature is 21 °C (70 °F) and inland areas around Launceston reach 24 °C (75 °F). Other inland areas are much cooler with Liawenee, located on the Central Plateau, one of the coldest places in Australia with temperatures in February ranging between 4 °C (39 °F) to 17 °C (63 °F). Autumn lasts between March and May and experiences changeable weather, where summer weather patterns gradually take on the shape of winter patterns. The winter months are between June and July and are generally the wettest and coolest months in the state, with most high lying areas receiving considerable snowfall. Winter maximums are 12 °C (54 °F) on average along coastal areas and 3 °C (37 °F) on the central plateau, thanks to a series of cold fronts from the Southern Ocean. Spring is a season of transition, where winter weather patterns begin to take the shape of summer patterns, although snowfall is still common in mountainous areas until October. Spring is generally the windiest time of the year with afternoon sea breezes starting to take effect on the coast.

TEMPERATE ZONE (Warm Summer, Cool Winter)

The coastal area of NSW as far north as Kempsey or Coffs Harbour, and including the inland areas of NSW, Victoria, all of South Australia and the Southern half of Western Australia. Inland Queensland west of Dalby.

Temperate climates are those without extremes of temperature and precipitation (rain and snow). The changes between summer and winter are generally invigorating without being frustratingly extreme. There are two types of temperate climate: maritime and continental. The maritime climate is strongly influenced by the oceans, which maintain fairly steady temperatures across the seasons. Since the prevailing winds are westerly in the temperate zones, the western edge of continents in these areas experience most commonly the maritime climate. Continentality increases inland, with warmer summers and colder winters as the effect of land on heat receipt and loss increases.

Within temperate zones areas can also be classified as cold semi-arid climates with cold winters.

MEDITERRANEAN CLIMATE

A Mediterranean climate is a particular variety of subtropical climate.

Perth to Adelaide – Warm to hot dry summers with occasional afternoon coastal sea breezes. The winters are mild or cool and bring most of the rainfall from May to August. The average annual rainfall is about 800 mm.

The summer temperature averages 29 degrees Celsius during the day and 17 degrees at night. The average winter temperature is 15-18 degrees Celsius during the day, and dropping to 9 degrees at night.

TROPICAL/SUBTROPICAL CLIMATE

Coastal NSW, North of Coffs Harbour, most of Queensland and the Northern Territory, and the northern parts of Western Australia. Tropical areas do not have frosts.
The humid subtropical climate dominates half of eastern Australia. This zone contains the only regions where soils are not acutely deficient in phosphorus, as well as the heaviest rainfall south of the Tropic of Capricorn, making it prime agricultural country, centred on towns such as Coffs Harbour, Grafton, Kempsey, Port Macquarie, Tamworth, and Moree.

Within tropical and subtropical zones, there are also areas with hot semi-arid climates.


Resources & Links:

http://www.bom.gov.au/iwk/climate_zones/index.shtml

Interesting articles:

https://www.anbg.gov.au/gardens/research/hort.research/zones.html

http://www.britannica.com/EBchecked/topic/322068/Koppen-climate-classification

The Köppen climate classification scheme divides climates into five main groups, each having several types and subtypes. Each particular climate type is represented by a 2 to 4 letter symbol.

Ref: Peel MC, Finlayson BL & McMahon TA (2007), Updated world map of the Köppen-Geiger climate classification, Hydrol. Earth Syst. Sci., 11, 1633-1644.

Koppen_World_Map