No, Blue is scheduled to operate 24 hours a day.
If you take it out of the pool, you might have incoherent values. Indeed, Blue takes a measurement every hour and sends it to the servers of Riiot Labs to be analyzed.
However, Blue is not designed to operate when the water temperature is below 5°. Please make sure to take it out of the water and put it in standby mode during the winterisation of the pool.