Wind comparison between SKY & Acurite (solved)

Tempest Owners
1

Thank you for the update and what the changes look to do. I thought it interesting to see that Sky may be underestimating the wind as I have identical height mounts of 25’ w/ Acurite and WF only 12" apart w/ no shaking and for the last 10 observation days of 24hrs each day finding 100% higher readings by the following percent differences to AcuRite for all types of weather conditions (expect snow).
% difference peak wind compared to AcuRite 5-in1
18%
21%
24%
38% (13mph vs. 17.9mph)
23%
21%
30%
29%
13%
16%
[low wind gust of 9mph, highest gust during 10 day observational period: 37.6mph]
the weather type doesn’t appear to impact the differences. It is notable for this site that
for the first 10 days of observation WF provided higher gusts and therefore suggests
great sensitivity than traditional anemometer cups. This study, along with: DP, Pressure, Temp.
and Rain will continue for 30 days and be reported here in future updates.

2

Thanks, Gary. We’ll take a look at your debug data and see what we can see.

3

Hi Gary. Thanks again for this report. We have taken a look at your wind data, comparing the SKY to your Acurite for the same time period (roughly the past 10 days). Here are plots of average and gust wind speed, SKY in orange and AcuRite in blue:

average

gust

As you can see, there’s pretty darn good agreement! If anything, the SKY reads higher gusts.

So, we’re not sure where you’re seeing the big negative % differences, but one theory is that you may be comparing the data at different time scales. On the graphs in the smart weather app, the time scale changes as you zoom in and out. Data is reduced or “bucketed” (explained more here: Data archive buckets explained). To compare apples to apples, be sure you’re comparing similar time scales. That probably means looking at the one-minute zoom level (you could also download the raw observations via the API or one of the third-party tools that uses it).

Does that make sense? If it still seems like your SKY is underestimating wind speed, please share more details about the specific dates and time periods and how you’re determining the % differences. The more data the better.

Thanks again!

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4

I’m in complete agreement with you. I do think there is an inertia affect reducing

AcuRite’s readings as the wind has to push the anem. cups and there’s friction

upon slowing.

Could not be happier. My % differences were only gusts at the end of 24hrs.

I find myself no longer using my AcuRite as my reference instrument.

Gary

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