Watering infrequently provides deep water sources that roots search for. Frequent watering promotes surface root growth. The length of watering is determined by how fast your sprinklers apply water. To measure this, put pans in your yard and water for 15 minutes. Measure the water depth and multiply by 4 - this is how much water per hour is being applied.
Most timers have a button for shutting down for rain.
Turn off main system master valve. This stops water from flowing to the system. Drain the mainline with manual drains. Be sure the individual circuit lines are drained and clear of water. Blowout if necessary.