Mechanical vs digital Christmas light timers

A dial with pins. It cannot be mis-programd in any interesting way, it does not forget its schedule in a power cut, and it costs very little.

Mechanical timers are unfashionable and they keep getting bought, because the failure modes of digital timers are worse. A digital timer that loses power forgets its program and comes back in a default state. A mechanical dial with the pins pushed down does not forget anything — the pins are the memory, and they are physical.

You push down a pin for each 30-minute block you want power. Coarse, but a Christmas display does not need minute accuracy.

Woods is a long-established name in this category and sells outdoor-rated versions. Check that the specific model is rated for outdoor use; the indoor and outdoor versions look similar in listings.

You still get the sunset-drift problem: a fixed clock does not know that sunset moved. If that bothers you, the photocell option above solves it and a mechanical timer never will.

Three grounded outlets, 7-day programming and a 15-amp rating in one weatherproof box. The amp rating is the spec that matters and this one does not cut it fine.

Buy the timer before you buy the last set of lights. Switching a display on and off by hand at an outdoor outlet lasts about four days before everyone gives up and leaves them on all night, which triples the running cost and shortens the life of everything.

The spec that decides a timer is its amp rating, and most people never look at it. An outdoor circuit is typically 15 amps. A timer rated at 10 amps plugged into that circuit is a 10-amp ceiling on your display whatever the breaker says, and exceeding it is how timers fail — often by welding their relay closed, which is a timer that never turns off again.

This DEWENWILS unit is rated 15 A with three grounded outlets and 7-day programming, and it is UL Listed. That last point deserves attention: certification is not universal in cheap outdoor timers, and it is the difference between a tested product and an untested one carrying your whole display.

Practical advice: program it indoors, on the kitchen table, before it goes outside. Digital timer interfaces are all bad, and they are worse in gloves, in the dark, at 25 degrees.

Three outlets also means one timer instead of three, which matters because each outdoor timer is itself a thing to weatherproof.

A photocell instead of a clock. Sunset moves by about 25 minutes between early December and late January, and this is the only control type that tracks it without you doing anything.

A clock timer set to 5:00 pm in early December is fifteen minutes late by the solstice and about twenty-five minutes early by the end of January. Nobody reprograms it. The lights come on in daylight for the last three weeks of the season, which is the single most common thing wrong with an otherwise good display.

A photocell fixes that by measuring actual darkness. BN-LINK's dusk-to-dawn unit is rated 15 A, has two grounded outlets and an ETL listing.

The catch is the other end of the night. Pure dusk-to-dawn runs until sunrise, which is fourteen hours in December. If you want off at 11:00 pm, you need either a combined photocell-plus-countdown unit or a smart plug with a sunset-offset schedule.

Sensor placement decides whether this works. It needs a clear view of the sky and must not see your own porch light, a neighbor's floodlight or a streetlamp. We have seen a display that never came on all season because the sensor was eight feet from a lamp post.