How Climate Affects Keyless Entry Fobs: From Freezing Winters to the UK’s Record-Breaking Heat

Keyless entry fobs have become standard in many modern vehicles, offering convenience and quick access without turning a key. But as weather in the UK grows more extreme, questions arise about how these smart keys cope with temperature swings. Whether it’s an icy January morning in Yorkshire or a scorcher of a summer’s day in London, climate can impact the way your key fob functions or whether it functions at all.

Let’s take a closer look at how temperature affects your fob, why even a brand-new battery can suddenly fail, and what you can do to prevent unexpected issues.

How Cold Weather Affects Keyless Fobs

Across much of the UK, winter temperatures often drop below freezing. While we tend to worry about the car battery in cold weather, key fobs are just as vulnerable.

The biggest issue is the lithium coin battery inside the fob. Cold temperatures significantly reduce battery performance even at just -5°C, the power output can drop noticeably. At -10°C, some fobs may stop responding entirely, even with fresh batteries.

There’s also the issue of condensation. Bringing your key fob from a warm house into a cold car, or vice versa, can cause moisture to build up inside the casing. Over time, this can affect the internal contacts or short the circuit board altogether.

Warning signs to look out for:

1. The car takes longer to unlock
2. The fob doesn’t respond until the second or third press
3. It works indoors, but fails after a night in a cold garage

How Heat Can Damage Keyless Fobs The Summer of 2022 as a Case Study

The summer of 2022 was a turning point for UK weather. For the first time, temperatures exceeded 40°C in parts of the country a level of heat most vehicles (and drivers) simply aren’t built for.

This kind of heat can cause serious problems for electronic devices, and key fobs are no exception. Left in a vehicle parked in direct sun, the temperature inside can soar past 60°C. At this point, plastic components may start to warp, rubber buttons can soften or crack, and cheap solder joints on the circuit board may weaken.

Batteries, too, suffer in the heat. Prolonged exposure can cause them to swell or leak, even if they’re relatively new. Budget batteries are particularly at risk, as they lack proper thermal protection.

Real-life examples from 2022:

• Several Audi owners in London reported that their fobs stopped working after just two hours parked in full sun
• A BMW key fob brought in by a Manchester client had warped from heat, and the battery had dislodged from its holder

How to Protect Your Key from Temperature Damage

The good news? You don’t need to be at the mercy of the weather. A few simple precautions can go a long way:

1. Never leave your fob in the car even if it’s parked on your own drive. Interior temperatures can climb dangerously high in summer.
2. Use a protective case or pouch silicone covers or cloth sleeves provide insulation and prevent dust and moisture from getting in.
3. Keep your key at room temperature store it in a drawer or bag rather than in the garage or near a window.
4. Replace the battery regularly every six months is a safe rule of thumb, even if the key seems to be working fine.
5. Avoid cheap batteries they’re more prone to failure in extreme heat. Brands like Panasonic, Maxell, or Varta offer better stability in changing conditions.

What to Do If Your Keyless Fob Stops Working

If your key fob has suddenly stopped working after a heatwave or frosty night, don’t panic and don’t feel you have to go straight to a dealership. In many cases, the issue can be diagnosed and resolved much faster and more affordably by a qualified specialist.

At Phoenix Car Keys, we offer:

1. Diagnosis and repair of keyless fobs
2. On-the-spot battery replacement (with warranty)
3. Reprogramming of existing keys
4. Same-day replacement, even if the original key is unresponsive

We cover a wide range of vehicle makes and models including Ford, Vauxhall, BMW, Jaguar and more and we offer mobile services if you’re stuck and need help fast.