When first pairing your Wave with your tablet or phone, your first measurements appear within 5 minutes. The temperature and humidity are ready to go, but the radon sensor will need some time (7 days) to adjust to the environment in order to deliver accurate results.
This calibration period is visible in the Airthings App (highlighted in yellow below):
Why is it 7 days?
The Wave has a radon sensor which takes hourly recordings of the radon in your environment, and these hourly readings are combined to give you consistent rolling averages. The Wave is designed for long term measurements, so the most reliable result is the long term average.
7 days is the minimum amount of time we recommend to gather a reliable amount of data, although we advise you to measure for 30 days before deciding whether any mitigation action is necessary. The longer you measure for, the more accurate your results will be.
Remember! Temperature and Humidity are measured every 5 minutes, while radon is measured hourly. :)