As published in BTR News 12 June 2026.
It is an increasingly common occurrence in the centres of large UK cities to experience windy conditions around the bases of tall buildings. They can deflect air down to ground level, causing uncomfortable wind chill on cold days and potentially unsafe conditions on the windiest days.
To minimise the risks associated with these issues local authorities will request that developers provide a Wind Microclimate Assessment to support planning applications, but these can be highly technical and confusing documents for the layman to read and are commonly misconstrued.
So how can the most common misconceptions of wind microclimate be demystified?
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Surely you can’t build a tower that tall without causing severe wind issues?
On a fundamental level, you might expect that once a building gets beyond a certain height the risks are simply too great, and it is no longer possible to build without causing severe wind issues at ground level. But the good news is that if developers and architects address and understand the wind conditions early in the process, then not only can a tall building not cause severe issues at ground level, but it can even have a beneficial impact relative to the existing conditions.
It may sound trite, but a building cannot either create or destroy the wind. Instead, it will deflect existing wind flow paths into different regions. For a badly designed building, this may mean concentrating airflow in commonly used areas and causing discomfort to pedestrians, but for a well-designed building we can deflect the wind away from people to places where it will not cause any harm. It all depends on the quality of the advice!
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What is the Lawson Comfort Criteria?
A Wind Microclimate Assessment will present conditions with respect to the Lawson Comfort and Safety Criteria, which was developed originally by Tom Lawson at Bristol University in the 1970s, and refined by the London Docklands Development Corporation (LDDC) in 1990 and then again by the City of London (CoL) in 2019.
You might see a reference to using the ‘Bristol’, ‘LDDC’ or ‘CoL’ version of the criteria for a development in say Cardiff, Manchester, or anywhere, and think “hang on, why have they used that when this building is nowhere near the London Docklands” but that is just telling you where the version was originally developed, and any of them can be used anywhere.
The differences between the different versions are mainly concerned with increasing the clarity of the categorisations over time, but they all share a common theme of expressing the levels of risk that wind speeds will be too strong for different activities, or even strong enough to blow someone over. Wind safety is based on a risk of something happening for 2 hours per year, and wind comfort for 5% of each season. It is important to realise this, as the results may suggest a location is “only” suitable for walking when actually it would also be suitable for standing for over 90% of the time. A good wind consultant can provide this context beyond the basic categories that are reported and will allow you to understand how the wind conditions will actually feel once a development is complete.
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How can you predict future wind speeds based on historic wind data?
The wind risk levels for a Wind Microclimate Assessment are generated by combining measured wind speeds with recorded historical wind statistics. Wind is by nature a chaotic system, so to obtain reliable wind statistics it is important to use a sufficiently large data set of recorded data (recorded over around 30 years).
The use of data based on the past 30 years can lead to questions of how robust Wind Microclimate Assessments are to climate change. Fortunately, GIA’s advanced climate engine can use large scale climate change models to generate accurate local future weather files for individual sites around the UK. This shows that the levels of extreme winds are not likely to worsen over the next century, so a Wind Microclimate Assessment undertaken today will be robust for the lifetime of the building in question.
Where climate change will impact comfort and safety is in terms of extreme heat, which is likely to become a lot more common and sadly could cause increased deaths. The good news is that, if a consultant can combine specialist knowledge of wind, solar radiation and climate change, then they can also help create spaces which will be robust against extreme heat events in the future, so help save lives!
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How can wind data from an airport be applicable to the microclimate in the middle of a town?
The data which is used to create the statistics for a Wind Microclimate Assessment is taken from a local airfield (or airport). This can lead to confusion when used for a development in a city centre, where the terrain is so different to the open space around an airfield. The reason for using airport measured data is that it is collected frequently and robustly, and it represents the main wind speeds and directions in the area.
These wind patterns are then run across an accurate 3D model of the development site and its surrounding buildings using computer simulations. The wind will interact with the 3D model generating accurate local predictions. If done correctly by a competent wind consultant, this will give reliable results for any urban location.
The best wind microclimate assessments do more than satisfy planning requirements – they help shape places where people want to live, work and spend time. Dispelling the myths surrounding wind studies allows project teams to focus on what really matters: delivering high-quality environments that balance design ambition with user comfort and safety.
Early engagement with a specialist consultant can make all the difference. At GIA, our team provides practical, evidence-led advice that helps unlock development potential, mitigate risks and keep projects moving forward with confidence. If wind microclimate is likely to be a consideration for your scheme, or related services such as climate and resilience, flood risk, daylight and sunlight or boundary mapping, the earlier the conversation starts, the greater the value it can deliver.
To discuss further reach out to Chris Harley or Jon Winchester.