As the temperatures drop, cold related battery issues climb. Although you can use our device anywhere, and in any condition that you would use your battery operated boom box, iPod or transistor radio, please be aware that the cold effects the power output of a battery so the batteries could be brand new (test and work just fine in warmer environment) but still not be able to deliver the punch needed for the Raticator to do its job. Many customers work around it by keeping the unit warmed during the day and arming it in the evening when rodents are likely to be more active.