Pressure measurement
Mean sea level pressure is measured by the indoor module.
Pressure trend
The little arrow appears next to the pressure to shows whether it's increasing or decreasing. The trend is calculated over the last twelve hours.
Mean Sea Level Pressure
In order to allow the comparison between different barometric pressures measured by different weather stations, it is necessary to match the barometric pressure measurements recorded at different altitudes: sea elevation, valley elevation, mountain elevation. To do so, the raw pressure measurements are adjusted by a standardized formula. The value resulting from this is called mean sea level pressure. Your Netatmo station displays the mean sea level pressure, meaning the pressure that the Netatmo station would measure if it were at sea level. The mean sea level pressure is also the value given by weather forecasts and reports on TV or the Web.
How does the station know its altitude?
When you setup the Netatmo Station with your smartphone, the Netatmo App uses the smartphone's GPS to localize your station and your altitude.
Did you know?
The indoor and outdoor barometric pressure is always the same. For that reason, the barometer sensor is located in the indoor module only.
Updated