Wind Speed Measurements




We have access to many meteorological sites around the country that give detailed data on wind measurement including access to NIWA wind maps. This information gives a good indication of the general wind conditions in your area. However, localised conditions can be very different.

Gaining a better idea of your wind conditions can be done in various ways to differing levels of accuracy:

Looking at relevant wind data and using local knowledge to assess if you are in a windy or sheltered spot compared to the local area. This is highly subjective and will only give a rough indication.

Using the Griggs Putnam Index of Deformity as shown below. This uses local conifer tree growth and gives a good indication of long term wind-speeds gathered over the lifetime of the trees. It is surprisingly accurate but is still somewhat subjective.

The most accurate method is to undertake a wind survey by installing an anemometer and taking readings. Ideally you would have a minimum of 1 year of data although longer would be more accurate. These would be compared to national figures to assess if the year was a standard one.

To reduce time (with a subsequent loss of accuracy) three months readings could be taken and then compared with a local site. This comparison can then be extrapolated to give an annual variation from the local site.

Griggs-Putnam Index of Deformity

Wind Speed I II III IV V VI VII
km/hr 11-14 14-18 18-22 22-25 25-29 29-32 36
Knots 6-8 8-10 10-12 12-14 14-16 16-18 20
m/s 3-4 4-5 5-6 6-7 7-8 8-9 10


Tecnico can help with all of these methods and are happy to advise you further.


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