Setting the “height above ground” to 0 for sea-level pressure

I know the directions say to enter in the estimated height above ground in the app for the sea-level pressure reading; but I’m curious if it’s ok to set it as “0” so that the app only uses the elevation? I’ve noticed that the sea-level pressure reading is closer to the correct value if the “height above ground” is set as 0ft.

You need to put the correct value in so that the calibration can be done properly.

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First you set the elevation. Then you set the AGL to the height from the ground to the Tempest Sensor.

Then you let it alone for a couple weeks to get a proper calibration. Don’t try to cheat the system. It’s designed self correct to be accurate.


Thanks! When I get the opportunity to go to the site, I’ll get my tape measure and calculate it.


Quick question @GaryFunk @gizmoev, Does the WF map on the app is calculating elevation relative to the ground itself or the surface it’s on? Why I ask is because it seems like it’s giving me an elevation of the roof itself and not the ground. If that’s the case, all I have to do is measure the height of the station from the roof.

The elevation of the device is measured relative to the ground. That being said, the ground elevation from the map in the app is likely derived from a digital elevation model (DEM) that itself will have some level of innacuracy. Therefore, if you have a method of calculating ground elevation at your Tempest site more accurately than the app map, you can use this to override the elevation derived from the DEM, and then calculate the height from the ground to the Tempest device.


I placed my phone on the ground and then took the GPS elevation reading and entered that number in the application.


Thanks! My iPhone 8 GPS elevation seems like it’s all over the place at times. I thought about using google earth to help me.

Hi gizmoev, my tempest is mounted 7 feet above ground on a pole.I set my station up on sunday july 19th an my pressure is still off. My question is I have 7.0 in my height above ground setting.Should I just put 7 in the setting?I wasn’t sure if the setting includes inches or if inches were necessary in the setting. I’m wondering if thats why my pressure is off some.Thanks Gary

The height is in feet only. The value after the decimal is in tenths of a foot and does not represent inches. What is your Station ID or the share link to it?

My station i.d. is 24245. I wiil go an change it to just 7

o.k. so I went in an changed it to just 7 clicked save and it reads 7.0 ft

Yes, 7.0=7 mathematically speaking. 7.0 feet does not mean 7 feet 0 inches to the software, it means literally 7.0 feet, meaning to the nearest tenth of a foot. Just like 7.1 feet does not mean 7 feet 1 inch. 7.1 feet would be 7 feet 1.2 inches. The app changing it to 7.0 is all normal as that is the precision they use in the app.

o.k. so thats alright. now 2 reporting stations near me give baro pressure 2.90 mine is 2.958 its not alot but will it even out over time?

I would suggest that you could be 10 feet off and not significantly alter the calculations. Don’t over worry it. If your ground level elevation is close to correct, you can safely estimate the height of the sensor above that. (example - I’m at 365 feet elevation, with the Tempest 10 feet higher. The correction for sea-level vs. station pressure is 12 mbar for me)

I assume you mean 29.90 and 29.958inHg, unless you are in a high flying craft of some sort.

The absolute accuracy of the pressure sensor is +/- 0.03" (relative accuracy is +/-0.003") so your reading could be 0.03" above or 0.03" below the actual value. Also, pressure can be different just a little ways away. I’d say your station is fine and I wouldn’t worry about it.

Give it time and don’t over think it. It will need time to calibrate.

alright, thanks alot.