Using an electric mower with wet grass is not impossible. However, it is not recommended. First, the efficiency of mowing will depend on how wet your grass is. If it sinks while you walk, an electric mower won’t work. Besides, an extra sharp blade is required to deal with wet grass. Moreover, it is obviously not safe to drag an extension cord around in the wet grass. Finally, wet grass might be stuck in the deck and prevent the motor from working correctly. Thus, it possesses a potential risk of damaging your machine. So, it should be better if you wait for the grass to dry and then mow them with ease.