I agree with @alexpikkert! If you have an Arduino bit you can program that to send the trigger on state change. I would think you would want to read the analog value and create conditionals to react accordingly with a delay of a few minutes or so.
Something like this should get you started (havent tested this yet):
int moistureValue = analogRead(rainSensor)
if(moistureValue <= somevalue) //change condition according to your sensor (add additional conditions, etc)
digitalWrite(cloudBit, HIGH) //cloudbit on
digitalWrite(cloudBit, LOW) //cloudbit off
delay(300000); // read sensor every 5 minutes, change to whatever value you need in milliseconds