Reconciliation between Vantage Pro and Weatherflow

What is the best way to go about reconciling the differances between the vantage pro (on the left) and Weatherflow (on the right). Specifically the difference in barometric pressure and humidity. The Air is located about 4 feet from the vantage pro, and about 1 foot lower.


I would first make sure you don’t have a defective barometric pressure device in your Air. I had several of those before WF was able to get the supplier to correct a defect in their manufacturing process. It’s easy to tell if you have such a defective unit by determining if your pressure is fluctuating with temperature.

As for humidity, there has been considerable discussion on Davis forums about issues with the accuracy of the humidity sensor that Davis uses. According to the manufacturer of the sensor, Davis is not handling them properly during the manufacturing process of the Vantage Pro and that leads to issues. What tends to happen is that when humidity is high, the Davis will tend to read too high as the humidity drops.

The VP humidity sensor also tends to read too dry when humidity is relatively low. So the bottom line is that the VP is not the best device to use as a tool for calibration. Some feel that having a fan aspirated unit makes things worse. On the other hand the VP barometric device seems to be very accurate.

My pressure does not fluctuate with the temperature. I did an addition check but this time called the airport for the official Sea Level Pressure. Both Weather Display and Weatherflow display the Sea Level pressure. The Vantage Pro was reading 29.703 in and the WeatherFlow reads 28.499 in. The airport was at 29.71 inches.

The only times I got errors of that magnitude was when I first received the Air and when temperature fluctuation played havoc with the pressure readings. I know you said you haven’t seen a correlation between temperature & pressure, so I’m not sure why the discrepancy if you have had the unit for some period of time. I’m assuming you have the correct altitude for your location.

I know you have most likely checked it but are you sure that you have the correct altitude entered into the WF app?

Looks like there is a stark correlation between temperature and pressure reported by your AIR unit. Something is not right. We’ll reach out via email and get you a replacement unit.


Yup, that was my first thought based on my own experience. Surprised he didn’t see that.