A mosaic of rainfall levels for all online public radars for Australia (excluding Norfolk Island). Rainfall levels derived from radars within the Australian Weather Watch Radar Network. The fifteen levels can be approximated to rainfall intensity values. Weather radars send out electromagnetic waves similar to wireless computer networks and mobile phones. The signals are sent out as short pulses which may be reflected by objects in their path, in part reflecting back to the radar. Weather radars are designed to detect rain drops, hail, snow and other forms of precipitation. The intensity of the returned signal is used as an estimate of rainfall intensity and location.
Dedicated Weather Watch radars should be online at all times, unless there are technical difficulties or scheduled maintenance. Part-time Windfinding radars have routine periods when weather watch coverage is not available. This normally occurs, up to 4 times a day, for approximately 1.5 hours. On some occasions, when dedicated radars are offline for long periods due to upgrades or maintenance, a non-public radar (usually an airport) may be substituted for the duration of the outage.