RainToday generates alerts directly on the device, so called “local notifications” (not to be mistaken with push notifications, which are generated on a server and can be sent manually). The more you use the mobile phone and the app the higher is possibility that you receive notifications. The app checks up to every 10 minutes in the background and sends an alert if rain is expected. The reliability of receiving is alerts is improved when you use the “My location” favourite rather than a standard location. During periods when your device is not normally used, for example at night, notifications are less likely.