The difference the day makes

You need a dry , or dryish,  five hours for a full cut of our front lawn because  if it rains the robot automatically returns to its base.    It also gets gunged up if the wet grass cuttings are  thick.

Today's forecast was for showers, but as none had materialised by late morning, I decided to start, and see what happened.

Very fortuitously the robot was just finishing the last row , and was reversing into its charging place, when the promised thunderstorm arrived.