With years of being told rain sensors dont work i can tell you things have changed. the old sensors used a material than when wet would cause the circuit to turn off, These days qaulity rain sensors actually also measure the evaporation rate which allows the controller to know when to turn the sprinklers back on.
For example if you have a downpore and it is a over cast day then the sensor might keep the system off for a single day or for 3 depending on the amount of water and the evaporation rate.
And a lot are now also available as wireless options allowing for optimal location installs of the sensor and no running of wires.