LED lighting is built to last, but Canadian winters tend to find the weak points. Cold snaps, trapped moisture, and the constant swing between freeze and thaw often cause failures that a milder climate wouldn’t trigger. Here's how to work through the possible causes.

Start With the Symptom, Not the Fixture

The way a fixture fails tells you where to look. No light at all usually means a dead driver, a blown fuse, or a break somewhere in the circuit. A fixture that flickers is often working through a loose connection or a driver that can't hold a steady output. Dim light tends to trace back to voltage drop or a driver on its way out. Discolouration is typically a sign of moisture inside the fixture or an LED chip starting to fail.

Before pulling a fixture apart, it helps to rule out the obvious first. Check that the transformer is on and set correctly, confirm nearby fixtures on the same run are behaving the same way, and look for anything visible like a cut wire or a loose connector. A five-minute check here can save an hour of unnecessary teardown.

Condensation and Moisture Intrusion

Every freeze-thaw cycle pulls moisture through seals and gaskets that looked fine back in the fall. Materials contract in the cold and expand as they warm, and that movement wears down seals until they stop sealing. It doesn't take a crack you can see. A hairline gap is enough for water to work its way in over a winter.

Fogged lenses, corroded contacts, and connections that stop making a clean electrical path are the usual signs. Check the LED driver compartment, the housing seams, and every wire connection for even a small amount of water. If the moisture is minor, drying the fixture out and resealing it often solves the problem. If corrosion has already set into the contacts or the driver, replacement is usually the more reliable fix, since a corroded connection tends to fail again even after you clean it up.

Voltage Irregularities in the Cold

Cold weather doesn't cause voltage drop on its own, but it stacks on top of the distance problem that's already there on a long run. Voltage will drop even more when there's a loose or corroded connection at a fixture.

Voltage should be measured at the fixture, not the transformer, to determine whether there's an issue with the voltage or the fixture. If the voltage at the fixture is low, the issue is likely in the wiring or the connections. If the voltage is fine and the fixture still isn't operating, it’s probably safe to say the issue is with the fixture or LED lamp. From there, re-tapping the transformer to a higher voltage, re-splitting a long run into shorter legs, or cleaning and tightening a corroded connection usually brings the voltage back where it needs to be.

Driver and Component Failure

The LED driver is usually the first thing to fail in extreme cold because it's the most electrically active and heat-sensitive part of the fixture or LED lamp. It's regulating current constantly, and the internal components that do that job have a temperature range they're designed to handle. Push them past the bottom of that range and they can shut down, cycle erratically, or fail outright.

A driver rated for a narrower temperature range than what your region experiences may fail the first time a deep freeze hits, even if everything else about the install was done right. When you replace the fixture, match its cold-weather rating to what the site will realistically face, not just what the spec sheet lists as a minimum.

Fixture Degradation Over Time

A fixture doesn't need to fail outright to be in trouble. UV exposure fades and weakens the materials over time. Ice puts repeated stress on housings and seals. Road salt works into metal components and corrodes them from the outside in. And the constant swing between summer heat and winter cold tires out every joint and seam in the fixture, season after season.

A lens that's gone brittle enough to crack didn't get that way overnight. A housing that's lost its flexibility, or a seal that no longer compresses like it did when new, started degrading long before anyone noticed. None of that counts as a failure by itself. It's an opening. A weak seal lets moisture in. A cracked lens lets in the cold and the road grime that follows it. The failures covered earlier often start right here.

Catching a fixture nearing the end of its life is worth the extra look during a seasonal check. Replacing one on your own schedule costs less and takes less time than an emergency call after a cold snap finishes the job it started years earlier.

Preventing the Next Failure

The fixtures and drivers going in should have a cold-weather rating that matches the climate. Look for CSA or C-UL certification specifically. Certification means the product has been tested for Canadian conditions, not just rated for outdoor use in general, so it's the clearest way to know a driver won't be the first thing to fail next winter.

Sealing and mounting matter just as much as the components themselves. A properly sealed connection with the right connector can hold up through years of freeze-thaw, while a shortcut taken during install could come back to cause issues a season or two later. Building a seasonal check into the maintenance schedule, ideally before the first hard freeze and again after the spring thaw, can help you catch small issues while they're still cheap to fix.

SiteOne Knows Cold-Weather Lighting

At SiteOne® Landscape Supply, we stock CSA or C-UL rated LED fixtures and drivers made to handle Canadian winters, along with sealed connectors rated for the same conditions. Our local branch teams can help diagnose a failure you're already dealing with or source the right replacement parts to get a system back online fast. Whether you're troubleshooting a fixture that failed last week or planning a system that needs to last the next 10 winters, stop by your nearest branch for the products and expertise to get it right.