We use WeatherBug and other weather radar and lightening detectors to determine whether the pool will remain open or close. For safety, we must clear the pool if lightening is detected within 12-15 miles even if we can't hear it and/or if it's raining so hard we can't see the bottom of the pool. If the forecast makes pool use unappealing or unsafe for more than 2 hours, we will close for the duration of the day or until the weather improves.