Yes, it is possible to use it without WiFi. But... I personally don't find the operability on the device optimal, so I prefer to use the app with WiFi. At night, my WiFi is deactivated and the alarm clock still works perfectly. The benefit of a WiFi connection because of evaluations etc. I find moderately useful, so I would rather recommend an older and cheaper variant if it is not about that and the use of the app. (see also my rating)