The tado° devices measure the temperature and humidity once a minute and use these values to control your heating system.
However, values in the applications are only updated on changes of at least 0.2 °C (temperature) or more than 5% (humidity). These thresholds optimize battery lifetime.
Regardless of these thresholds the devices report their current temperature at least every 20 minutes. When the apps have not received an updated temperature value for more than 30 minutes, they show that currently no remote access is possible.