Draft. These pages were imported from the ARC Technical Criteria document (16 April 2026) and have not yet been reviewed in this format. Several thresholds are still being settled and are flagged on the pages concerned.

Climate and weather

Building performance is normally reported against the 'current climate', but that baseline is itself moving. Performance now has to be assessed against both current and predicted future extreme weather.

Changes in global and regional climates, and in the frequency and intensity of extreme weather - rainfall, wind, humidity, heat and cold - are now occurring, and are increasingly affecting the performance of long-lived structures such as buildings, and their occupants.

This is because of both:

• the gradual increase of average annual temperatures, and - significantly -
• the increasing frequency and intensity of dangerous hot weather events such as heatwaves.

The 'current climate' is a moving baseline

Building performance is typically reported relative to the 'current climate' - which is changing globally, with changes varying regionally and locally.

The current climate is defined according to measured conditions over an agreed period of time, typically 30 years. Different time periods or benchmarks are used for different purposes, and may or may not be universally used across governments and organisations.

Benchmarks are periodically updated. For example, the UK's Met Office has recently updated UK regional benchmarks for heatwaves as a result of the changing climate. Note that different regions have different benchmarks, to reflect regional variations in climate. See defining heatwaves.

What this means for assessment

ARC recognises that building performance is usefully assessed relative to the 'current climate' in any particular climate zone, climate region, or even relative to the climate in a very specific locality.

Because of faster than predicted climate change, building performance now needs to be assessed relative to both current and predicted future extreme weather events - particularly extremes of heat and humidity, that is, heatwaves.

This is why the heat refuge is a required part of an ARC-compliant building, and not an optional extra.

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Source: ARC Technical Criteria - ARC Protocols for Cool Buildings - Climate and Weather
Overview · confidence high · Imported 2026-08-29, not yet reviewed · next review 2026-11-29
Tags: climate, heatwaves, benchmarks, overview
Citation key: climate-and-weather