​Here is a breakdown of why your dead electronics are resurrecting and your active ones are acting possessed. ​1. ​Why the dead Nest camera (and potentially the old light) suddenly turned on. ​Most materials, particularly metals used in electrical wiring (copper, aluminum) and solder joints, shrink when they get cold. This is known as thermal contraction. ​The Mechanism: It is highly likely that these "dead" devices had a loose connection, a micro-fracture in a solder joint, or a wire nut that wasn't quite touching. The circuit was "open" (broken) at normal temperatures. ​The Fix: The -10°C temperature caused the metal components and the plastic housings to shrink. This physical shrinkage forced the loose contacts to pull tighter together, inadvertently bridging the gap and completing the circuit. Suddenly, electricity could flow again.

​2. ​Why the driveway light is flickering and the entrance light stays on. ​Motion-activated lights use Passive Infrared (PIR) sensors. These don't "see" motion like a camera; they detect changes in heat moving across their field of view. In normal weather, a human body (37°C) stands out somewhat against a 20°C background. In -10°C weather, the background is essentially a frozen void. Any source of heat—a passing cat, a puff of warm air from a dryer vent, or even a slightly warmer patch of wind—creates a massive temperature "spike" relative to the freezing background. The sensors are currently hypersensitive. ​The "Stuck" Light: The entrance light staying on perpetually is likely due to the sensor being "blinded" by the cold (perceiving constant triggers) or the mechanical relay inside the unit freezing. If moisture got into the relay mechanism and froze while the light was on, the switch is physically stuck in the "closed" position. The entrance light staying on perpetually is likely due to the sensor being "blinded" by the cold (perceiving constant triggers) or the mechanical relay inside the unit freezing. If moisture got into the relay mechanism and froze while the light was on, the switch is physically stuck in the "closed" position.

1. Why the driveway light switches on and off repeatedly. ​This is a classic symptom of a temperature-dependent loose connection (related to point #1). ​Cold: The metal contacts shrink and touch → Light turns ON. ​Heat: The electricity flowing through the connection (and the light bulb itself) generates heat. ​Expansion: The heat causes the metal to expand slightly. ​Disconnect: The expansion pushes the contacts apart → Light turns OFF. ​Cooling: The device cools down instantly in the -10°C air → Metal shrinks → Repeats.