LawnCheck will block irrigation only if the current zip code weather information is reporting rain at the time that the irrigation command is sent.
There are situations where the zip code weather information will not provide 100% accuracy for rain blocking. This is especially true in areas of micro-climates, or when weather patterns change quickly.
In many cases a local rain sensor will provide more accuracy in blocking irrigation during rain. The combination of a local rain sensor along with using the zip code weather information provides the best method because the zip code weather information can many times provide rain information before it actually begins to rain, preventing irrigation in the hours prior to a rain event.
LawnCheck's RainBrain feature can prevent irrigation immediately after periods of rain if a local rain sensor is used. Most modern rain sensors will continue blocking irrigation for a period after rain has stopped. In many cases these sensors can dry out too quickly. RainBrain ensures that irrigation is either blocked or significantly reduced within the 24 hour period after rain has stopped.