NCC Climate Zones Explained: The 8 Zones, How to Find Yours, and What Changes Between Them (2025)

Every energy efficiency and condensation rule in the National Construction Code starts with one question: which climate zone is the site in? The answer changes the insulation you specify, whether the wall needs a drained and ventilated cavity, how the roof space is ventilated, how dark the roof can be, and which NatHERS targets a rating has to meet. Sydney is two zones. Melbourne and Ballarat are different zones. Brisbane and Toowoomba are different zones. This guide explains the eight NCC climate zones, how to find the right one for an address, and exactly what NCC 2025 changes between them.

The short answer

The NCC divides Australia into eight climate zones, numbered 1 (hot and humid, Darwin) to 8 (alpine, Thredbo). The Australian Building Codes Board (ABCB) built them from Bureau of Meteorology data by grouping places with similar heating and cooling needs. The NCC glossary defines a climate zone as an area defined in Figure 2 of Volume One and in Table 3 for specific locations, "having energy efficiency provisions based on a range of similar climatic characteristics". Find your zone on the ABCB Climate Map by address or postcode, not from old local-government-area lists, which the ABCB now says are no longer reliable.

The zone then drives Part 13 (energy efficiency) and Part 10.8 (condensation management) of the ABCB Housing Provisions for houses, and Section J and Part F8 of Volume One for everything else. NCC 2025 raises the stakes in the cooler zones: in climate zones 6, 7 and 8 a framed external wall must now have a drained and ventilated cavity, and the roof space must be ventilated to stated opening sizes.

1. The eight zones, with the places the code names

The zone names below are the ABCB's. The example locations come from NCC 2025 Volume One, Table 3, which lists 140-odd towns and their zones and is the same table the glossary points to.

Three things in that table catch people out.

• Sydney is two zones. Table 3 lists Sydney East as zone 5 and Sydney West as zone 6. A house in Penrith or Campbelltown is designed to different insulation tables, and different condensation rules, from the same house in Manly. Wollongong and Newcastle are zone 5.

• Altitude beats latitude. Toowoomba is zone 5 while Brisbane, 120 km away, is zone 2. Armidale and Orange are zone 7, the same zone as Hobart and Canberra. The Snowy Mountains resorts and the Victorian ski fields are zone 8, islands of alpine inside zone 7 country.

• The coast is not one zone. Perth is zone 5 but Albany is zone 6; Adelaide is zone 5 but Victor Harbor and Mount Gambier are zone 6; Brisbane is zone 2 but Cairns and Townsville are zone 1.

2. How to find the climate zone for an address

Use the ABCB Climate Map. It is an interactive map, licensed under Creative Commons Attribution 4.0, and it takes a street address or postcode. Its FAQ is explicit: do not use older references that tied climate zones to local government area boundaries, because the boundaries have moved and those references are no longer reliable. If you are working from Table 3 in Volume One instead, use it for the towns it names and check the map for anything between them, because a zone boundary can run through a council area.

Record the zone on the drawings and in the energy report. Building surveyors and certifiers check it first, because every table that follows depends on it, and a wrong zone is a wrong specification everywhere at once.

If you run projects in AEC Assistant, the climate zone is worked out from the site address when the project is created and sits in the project's site information beside the planning zone and overlays, so every question you ask about that project is answered against the right zone.

3. NCC climate zones are not NatHERS climate zones

This is the most common confusion on the topic. The NCC has 8 climate zones. The Nationwide House Energy Rating Scheme (NatHERS) has 69, each with its own hourly weather file, and the NatHERS software simulates a dwelling against the weather file for its NatHERS zone. Two houses in the same NCC zone can sit in different NatHERS zones and get different star ratings for the same design.

The two systems do different jobs. When a house is assessed on the NatHERS pathway, the star rating and the heating and cooling load limits are set by the NatHERS zone. When it is assessed on the elemental Deemed-to-Satisfy pathway in Part 13 of the Housing Provisions, the R-values, glazing and solar absorptance limits are read from the NCC zone. Both numbers belong on the energy report. An assessor who quotes "climate zone 6" without saying which scheme is describing Melbourne on one scale and something between Tullamarine and Moorabbin on the other.

4. What changes between zones for a house (Housing Provisions Part 13)

Part 13 of the ABCB Housing Provisions is the elemental route to the energy efficiency Performance Requirement for Class 1 houses and their Class 10a garages. Almost every clause in it is indexed by climate zone.

• Roof and ceiling insulation (13.2.3). Clause 13.2.3(1) sends each climate zone to its own pair of tables, 13.2.3a to 13.2.3r, and the minimum R-value inside each table moves with roof ventilation, whether there is reflective insulation under the roof, and the solar absorptance of the roof surface. Reflective insulation must face downward in zones 3 to 8 (13.2.3(2)(c)). In zones 1 to 5 the roof surface must have a solar absorptance of not more than 0.64 (13.2.3(10)), which rules out most dark roofs in the warm half of the country.

• External walls (13.2.5). Wall insulation is again read from a table per zone, 13.2.5a to 13.2.5o, and lightweight walls in zones 2, 4, 5, 6 and 7 add R0.3 to the tabled figure (13.2.5(2)). In zones 1 to 5 the outer wall surface must have a solar absorptance of not more than 0.7 (13.2.5(3)). Metal-framed walls need a thermal break of at least R0.2 where the cladding is fixed directly to the frame (13.2.5(5)).

• Glazing, floors and shading. The remaining Part 13 clauses for windows, floors and shading each carry their own zone-indexed tables, and the NCC 2025 edition keeps the 7-star equivalent that arrived in NCC 2022.

The practical point: two identical house designs, one in zone 2 and one in zone 7, are different specifications. Copying a Brisbane detail set to a Canberra project is a non-compliance waiting to be found at certification.

5. Condensation: the NCC 2025 change that hits zones 6, 7 and 8 hardest

Condensation management is where NCC 2025 moved furthest, and the move is organised by climate zone. Part 10.8 of the Housing Provisions (Part F8 of Volume One for apartments, and now also Class 3 hotels and hostels and Class 9c aged care) introduces the defined term "control layer", sets vapour permeance limits for climate zones 1 and 3 for the first time, and makes a drained and ventilated wall cavity mandatory in zones 6, 7 and 8.

Reading clause 10.8.1 in order:

• Any pliable building membrane or sarking used as a control layer must comply with AS 4200.1 and be installed to AS 4200.2 (10.8.1(1)).

• Any control layer between the cladding and the outside face of the primary insulation must achieve the vapour permeance in Table 10.8.1 for the zone (10.8.1(2)). In zones 4 and 5 that is at least 1.1403 µg/N.s without a cavity, a class 4 membrane in AS 4200.1 terms. In zones 6, 7 and 8 the "no cavity" column is simply X: not permitted.

• A wall with no membrane and no water barrier outside the insulation must have a drained and ventilated cavity in every zone (10.8.1(3)).

• The cavity itself must be at least 12 mm deep, formed with battens or spacers, unobstructed by any control layer, drained to the outside at each storey where it is compartmentalised, and ventilated with openings of at least 1,000 mm² per metre of wall at the base and the top, or at each storey (10.8.1(4)).

• None of this applies to single-skin masonry, single-skin concrete, full insulated sandwich panel walls, walls outside the building envelope, or any part of a wall below natural ground (10.8.1(5)).

The explanatory note under the clause gives the physics in one line: in cooler climates a more vapour-permeable outer layer lets the wall dry outward, while in the tropics a less permeable layer stops outdoor moisture being driven in. Open-cell insulation such as glasswool is highly permeable; closed-cell foams are not. The note also spells out that in zones 6, 7 and 8 masonry veneer and cavity masonry walls are included, and must incorporate a drained and ventilated cavity built to 10.8.1(4).

Roof space ventilation in zones 6, 7 and 8

The same three zones carry the roof rules. Where the insulation is on the ceiling (not parallel to the roof), 10.8.3 requires a roof space at least 18 mm high above the insulation, ventilated to outdoor air per Table 10.8.3: for a pitch of 10° to 75°, 7,000 mm² per metre at the eaves and 5,000 mm² per metre at the ridge; for a pitch under 10°, 20,000 mm² per metre at low level, or at two opposing ends of a gable roof. Where the insulation follows the roof plane (skillion and cathedral roofs), 10.8.4 requires an 18 mm space above the insulation, the same opening areas (20,000 mm²/m low and 5,000 mm²/m high for roofs of 10 m² or more), and any control layer directly above the insulation must have a vapour permeance of at least 1.14 µg/N.s (10.8.4(2)). Concrete roofs, sandwich-panel roofs, roofs subject to BAL-FZ under AS 3959, and tiled roofs with no control layer above the insulation are exempt from both clauses.

Roof cladding profiles count toward the opening area if they connect to the roof void and are not blocked by sarking or insulation, and vermin or ember mesh is fine as long as air and water still get through. The explanatory notes carry three worked figures for multi-pitch and mansard roofs.

6. Apartments and commercial buildings: Section J and Part F8

Volume One uses the same eight zones. Section J's Deemed-to-Satisfy provisions for the building fabric, glazing and services carry zone-indexed tables in the same way Part 13 does for houses, and NCC 2025 tightens the Section J energy efficiency provisions for Class 3 and Class 5 to 9 buildings as a step toward near-net-zero operational energy. Part F8 mirrors Part 10.8: clause F8D3 and Table F8D3 carry the wall vapour permeance and cavity requirements for a Class 2 sole-occupancy unit, and NCC 2025 extends the Part to Class 3 and Class 9c buildings. If you design apartments, read F8D3 next to 10.8.1; the tables are laid out identically by climate zone.

7. Which edition applies, by state

The zone-specific condensation rules above are NCC 2025 provisions, and NCC 2025 is not yet in force everywhere. As at September 2026 the ABCB's adoption page shows Victoria, Tasmania, Western Australia and the ACT applying it from 1 May 2026 (WA and the ACT with 12-month transition periods), New South Wales, Queensland and South Australia's building code from 1 May 2027, and the Northern Territory not adopting it. Under NCC 2022 the condensation provisions covered zones 4 to 8 only and did not make the cavity mandatory, so a Sydney project certified under NCC 2022 in 2026 and the same project certified under NCC 2025 in 2027 have different wall build-ups. Our state-by-state adoption guide tracks the dates and transition rules as each jurisdiction confirms them.

8. A checklist before the energy report is signed

• Climate zone confirmed on the ABCB Climate Map by address, written on the cover sheet and in the energy report.

• NatHERS zone stated separately if the NatHERS pathway is used.

• Roof and wall solar absorptance checked against 0.64 and 0.7 in zones 1 to 5.

• Wall membrane class chosen from Table 10.8.1 for the zone and cavity type, and the cavity detailed to 10.8.1(4) where it is required.

• Roof space ventilation openings scheduled to Table 10.8.3 or 10.8.4 in zones 6, 7 and 8.

• Edition in force for the state and lodgement date confirmed, because the condensation clauses differ between NCC 2022 and NCC 2025.

Sources: NCC 2025 Volume One, Glossary (climate zone) and Table 3 (Climate zones for thermal design); ABCB Housing Provisions 2025 clauses 10.8.1, 10.8.3, 10.8.4, 13.2.3 and 13.2.5 and Tables 10.8.1, 10.8.3 and Explanatory Table 10.8.1; NCC 2025 Volume One F8D3; ABCB Climate Map and its FAQ (CC BY 4.0); ABCB "NCC 2025 condensation mitigation changes"; ABCB "NCC 2025 state and territory adoption information"; NatHERS "Climate zones and weather files". Figures verified against the ABCB's published text on 4 September 2026. Diagrams by AEC Assistant. This article is general guidance; the building surveyor or certifier for your project determines compliance.