Rain Alarm OSM Pro for Android warns you against precipitation by a silent alarm. You can watch what is coming by the up-to-date radar animation. The supplied widgets can help you monitor the precipitation situation without alarms. It uses OpenStreetMap as background.
Full Specifications
What's new in version 3.3.1
Version 3.3.1 search radius can be set visually, earch radius can be shown on map, added new setting for search sector, and server changes.