Connect all the (colored) hot wires together. Connect all the (white) neutral wires together.
The white neutral wire out of a light fixture must be connected to neutral. The black hot wire out of a light fixture must be connected to hot and a white wire (such as coming from a switch) may not be used for this connection.
Stick to your lawn watering schedule until it really starts to pour. After the storm you have only the same number of rest days you always had and then you need to start watering again.