The Rain Radar in Observations shows you the observed rain picked up by the meteorology office ground office radars around your location for the last two hours. The availability and accuracy of this data depends on the quality of data available from the local meteorology services and ground based radars they have deployed.
Lightning can be overlaid on the map or toggled off.
To view the map options, tap on the Map Options drop-down box in the top right corner of the screen. From there you can toggle the options to choose your preferred colour choice and Lightning overlay.