Weather files for Aotearoa New Zealand

The weather files contain data on Aotearoa New Zealand’s climate. The data helps technical experts complete energy and hygrothermal modelling for building designs. 

The files available on this page were developed by the National Institute of Water and Atmospheric Research (NIWA) and reviewed and tested by technical experts from the Building Research Association of New Zealand (BRANZ) and Kāinga Ora – Homes and Communities. 

The Ministry of Business, Innovation and Employment (MBIE) released the weather files in October 2024. 

Types of weather files available

Typical Meteorological Year (TMY3) files for the present climate

The present-climate TMY3 weather files represent the typical Aotearoa New Zealand climate conditions in 2024. These TMY3 weather files should now be used instead of the outdated TMY2 files created by NIWA in 2008.

A Typical Meteorological Year file has the hourly records for an artificial year created from 12 representative months. The chosen months are each typical of that month’s weather records over a period of 10 years or more. 

They are intended for:

• building energy and thermal performance analysis
• demonstrating compliance with Building Code clause H1 Energy Efficiency, using the modelling methods described in verification methods H1/VM1 and H1/VM2.

The TMY3s are in the .epw file format for use in EnergyPlus or other compatible simulation software. 

Download the TMY3 weather files for present climate [ZIP 4.7MB]

Design Summer Year (DSY1) files for the present climate

These DSY1 weather files represent a year with a moderately warm summer (warmer than typical for the location, with a return period of about 7 years). 

Use the DSY1 weather files when evaluating overheating risk within buildings. The Chartered Institute of Building Services Engineers’ (CIBSE) technical memorandum:  TM59 ‘Design methodology for the assessment of overheating risk in homes’ is an example of a commonly used evaluation method of overheating risk.  DSY1s include a single year’s observed data, rather than a year made up of monthly values from different years. 

The files are in the .epw file format for use in EnergyPlus or other compatible simulation software.

Download the DSY1 weather files for present climate [ZIP 4.7MB]

Future-projected climate TMY3 and DSY1 weather files

As well as the TMY3 and DSY1 present climate weather files, you can download NIWA future projected weather files representing 3 different climate change scenarios.

NIWA’s future projected weather files are based on 3 different Intergovernmental Panel on Climate Change (IPPC) Shared Socioeconomic Pathways (SSP) and their timeframes. The 3 different scenarios are: 

• M1: representing SSP1-2.6 for 2040 with an approximate mean temperature increase of 0.5°C from present day (2024), or 1.5°C above pre-industrial climate
• M2: representing SSP2-4.5 for 2050 with an approximate mean temperature increase of 1.0°C from present day (2024), or 2.0°C above pre-industrial climate
• M3: representing SSP3-7.0 for 2070 with an approximate mean temperature increase of 2.0°C from present day (2024), or 3.0°C above pre-industrial climate.

Download M1 future-projected TMY3 weather files [ZIP 4.3MB]
Download M1 future-projected DSY1 weather files  [ZIP 4.3MB]

Download M2 future-projected TMY3 weather files [ZIP 4.3MB]
Download M2 future-projected DSY1 weather files [ZIP 4.3MB]

Download M3 future-projected TMY3 weather files [ZIP 4.3MB]
Download M3 future-projected DSY1 weather files [ZIP 4.3MB]

Moisture Design Reference Years (MDRY) weather files

These weather files are for hygrothermal analysis of moisture and mould risks such as those in ANSI/ASHRAE Standard 160. The MDRYs consist of a single year’s observed weather data. 

They are provided in the .wac format for use in WUFI (Wärme Und Feuchte Instationär) or other compatible simulation software.

Download the MDRY weather files for present climate [ZIP 1.6MB]

Aotearoa New Zealand areas included in the weather files

These weather files include 18 different areas. Each area represents a climate zone that NIWA assessed as sufficiently uniform in terms of average temperature, humidity, wind and incident solar radiation. These are the key weather elements in modelling energy balance in buildings. 

The 18 climate zones use the territorial authority boundaries (except for Rangitikei and Waitaki districts). They are sub-sets of the 6 climate zones set out in the acceptable solutions and verification methods for Building Code clause H1. 

Each weather file includes a 2-letter code in its file name to identify the climate zone that it represents. As shown on the map in Figure 1 below, the climate zone codes and placement in the 6 H1 climate zones are as follows. 

H1 climate zone 1:

• ‘NL’ - Far North District, Whangārei District and Kaipara District. Based on weather data from Kaitāia.
• ‘AK’ - Auckland and the Thames-Coromandel District and are based on weather data from Auckland.
• ‘BP’ - Western Bay of Plenty District, Tauranga City, Whakatāne District, Kawerau District and Ōpōtiki District. Based on weather data from Tauranga

H1 climate zone 2: 

• ‘HN’ - Hauraki District, Waikato District, Matamata-Piako District, Hamilton City, Waipā District, Ōtorohanga District, South Waikato District and Waitomo District. Based on weather data from Hamilton
• ‘NP’ - New Plymouth District, Stratford District, South Taranaki District and Whanganui District. Based on weather data from New Plymouth
• ‘EC’ - Gisborne District, Wairoa District, Hastings District, Napier City, Central Hawke’s Bay District. Based on weather data from Napier

H1 climate zone 3:

• ‘MW’ - part of the Rangitikei District that is south of 39o50’S (-39.83), the Manawatu District, Palmerston North City, Horowhenua District and Kāpiti Coast District. Based on weather data from Paraparaumu
• ‘WN’ - Porirua City, Hutt City and Wellington City. Based on weather data from Wellington
• ‘NM’ - Tasman District, Nelson City, Marlborough District and Kaikoura District. Based on weather data from Nelson

H1 climate zone 4:

• ‘RR’ - Rotorua District. Based on weather data from Rotorua
• ‘TP’ - Taupō District, Ruapehu District, and the part of the Rangitikei District that is north of 39o50’S (-39.83). Based on weather data from Tūrangi
• ‘WI’ - Tararua District, Upper Hutt City, Masterton District, Carterton District and South Wairarapa District. Based on weather data from Masterton
• ‘WC’ - Buller District, Grey District and Westland District. Based on weather data from Hokitika

H1 climate zone 5:

• ‘DN’ - part of the Waitaki District on the true right of the Otekaieke river, Dunedin City and the Clutha District. Based on weather data from Dunedin
• ‘CC’ - Hurunui District, Waimakariri District, Christchurch City, Selwyn District, Ashburton District, Timaru District and Waimate District. Based on weather data from Christchurch.

H1 climate zone 6:

• ‘QL’ - Queenstown-Lakes District. Based on weather data from Queenstown
• ‘OC’ - Mackenzie District, the part of the Waitaki District on the true left of the Otekaieke river and the Central Otago District. Based on weather data from Lauder
• ‘IN’ - Southland District, Gore District and Invercargill City. Based on weather data from Invercargill.

Figure 1: Map of the 18 weather file climate zones.png

Design condition information in the weather file headers

The file headers provide information on design conditions, typical/extreme periods, and monthly mean ground temperatures identified by NIWA based on observed weather data.

This information should be used instead of tabulated values from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). 

For software compatibility this information is documented in the same format shown in the ASHRAE Handbook.

 2013 ASHRAE Handbook - Fundamentals - codehub.building.govt.nz 

If processing the weather files with the EnergyPlus Weather File converter tool, note that the weather file converter will not read this information from the file header. It instead uses standard tabulated data from the ASHRAE Handbook - Fundamentals.

Background on the Aotearoa New Zealand weather files

Read the National Institute of Water and Atmospheric Research (NIWA) report for information on how the Aotearoa New Zealand weather files were developed.

Read the NIWA report [PDF 2.1MB]