When it comes to creating atmospheric outdoor lighting in the UK, festoon lights are a popular and stylish option. From back garden patios to pub terraces, their warm glow adds charm and ambience to any setting. But there's one question homeowners and commercial users often ask before buying or installing them:

Are festoon lights waterproof?

The answer isn’t just a simple “yes” or “no.” It depends entirely on IP ratings—a system used to measure how resistant a product is to the elements. In this guide, we’ll break down everything you need to know about waterproofing festoon lights, focusing on IP ratings, weather resistance, safety tips, and what to look for when shopping in the UK’s often damp and unpredictable climate.

What Does “Waterproof” Really Mean for Festoon Lights?

“Waterproof” is a common term that gets thrown around a lot in marketing. But in technical terms, no outdoor electrical light is 100% waterproof in all situations—especially not when submerged in water. What you really want is a light system that is weatherproof, meaning it can withstand rain, wind, and general outdoor exposure.

That’s where IP ratings come into play.

Understanding IP Ratings

IP stands for Ingress Protection. It’s an international standard used to classify the level of protection a product has against solids (like dust) and liquids (like rainwater).

An IP rating has two digits:

• The first digit refers to protection from solid objects and dust (ranging from 0 to 6).

• The second digit refers to protection from moisture and liquids (ranging from 0 to 9).

For example:
IP44 = Protected against solid objects larger than 1mm and splashing water from all directions.
IP65 = Dust tight and protected against water jets.

Let’s break down the most relevant IP ratings you’ll encounter when choosing festoon lights.

Common IP Ratings for Festoon Lights

1. IP20 – Indoor Use Only

• Protection Level: Limited protection against solid objects; no protection against water.

• Use Case: Only safe for indoor use—under no circumstances should these be used outdoors.

2. IP44 – Splashproof and Suitable for Most UK Gardens

• Protection Level: Protected against solid objects larger than 1mm and water splashes from any direction.

• Use Case: Suitable for sheltered outdoor use (e.g. under a canopy, pergola or eaves). These are the minimum standard for garden lights exposed to UK drizzle and damp air.

3. IP65 – Jet-Proof and Heavy-Duty Outdoor Use

• Protection Level: Dust-tight and protected from water projected by a nozzle (jets of water).

• Use Case: Ideal for fully exposed outdoor areas. Handles strong rain, hose cleaning, and general UK weather like a pro.

4. IP67 – Temporary Water Immersion

• Protection Level: Can be temporarily submerged in water up to 1 metre.

• Use Case: Suitable for extreme weather or installations near ponds or wet zones, but not required for general garden lighting.

Are All Festoon Lights Waterproof?

No, not all festoon lights are created for outdoor use. Many decorative or party-style lights with exposed bulbs or low IP ratings are intended only for indoor environments.

How to Know If Your Festoon Lights Are Waterproof:

• Look for a clearly marked IP rating on the packaging or product description.

• Check if both the cable and the bulb holders are rated for outdoor use. Some cheaper sets might have outdoor-rated cable but indoor-only bulb sockets.

• Make sure the connectors (if using connectable sets) are also sealed and weatherproof.

Do Bulbs Have Their Own IP Rating?

The bulb itself doesn’t usually carry an individual IP rating, but the bulb holder or socket does. A well-sealed bulb holder is crucial for preventing water ingress.

That said, if you’re using glass filament bulbs, it’s important to ensure the entire lighting system is installed in a way that avoids pooling water or exposure from underneath.

Waterproof Cable vs. Waterproof System

Some sellers may advertise “heavy-duty waterproof cable,” which can be misleading. While rubber-sheathed cables may resist water exposure, that doesn’t mean the whole lighting system is suitable for rain.

Always ensure:

• Connectors are sealed with gaskets or twist-lock covers.

• Cable joins are not exposed to the elements.

• Power plugs are used with IP66-rated outdoor sockets or waterproof enclosures.

Best Practices for Outdoor Use in the UK

1. Install With the Weather in Mind

The UK climate can shift quickly from sunny to stormy. If you’re setting up festoon lights in a high-exposure area:

• Choose IP65-rated or higher.

• Use support wires to keep the cable taut and avoid sagging or pooling water in the sockets.

• Avoid hanging lights where bulbs point upward—water can sit in the bulb base and damage the fitting.

2. Use a Weatherproof Outdoor Socket

Even if your lights are rated for outdoor use, the plug and socket must also be protected:

• Use a socket box or outdoor enclosure.

• Avoid using indoor extension leads or sockets exposed to the elements.

3. Bring Indoors When Not in Use (Optional)

If you’ve got lights that are only IP44 rated and you're expecting high winds, snow, or torrential rain, it’s a good idea to take them down and store them safely.

Commercial Settings: What to Consider

If you’re using festoon lighting in a commercial outdoor space like a pub garden, hotel courtyard, or outdoor café, go for the most robust IP rating you can afford—ideally IP65 or above.

These lights:

• Offer reliable performance in all weather.

• Are built with heavy-duty rubber cabling and sealed bulb sockets.

• Meet safety standards required for public-facing environments.

In many cases, commercial festoon sets also come with connectable systems, allowing you to expand the length while maintaining weatherproof integrity throughout.

What If Water Gets Inside a Bulb or Socket?

Signs of Water Ingress:

• Flickering lights

• Tripped circuit breaker

• Corrosion inside the bulb holder

• Clouded or foggy bulbs

If this happens:

1. Unplug the lights immediately.

2. Dry out the cable and socket.

3. Replace any affected bulbs or fittings.

4. Check for cracked seals or loose fittings.

5. Consider upgrading to a better IP-rated system.

Solar Festoon Lights: Are They Waterproof Too?

Yes, most modern solar-powered festoon lights are designed with waterproof or weatherproof housings. The solar panel itself usually carries an IP65 or IP67 rating, and the lights are at least IP44.

But:

• Always position the solar panel at an angle to allow rain to run off.

• Avoid water pooling on top of the panel or around connectors.

• Regularly wipe down the panel to keep it working efficiently.

Quick IP Rating Cheat Sheet for UK Festoon Buyers

Final Thoughts: Choose Festoon Lights That Match the Weather

To sum up: Yes, festoon lights can be waterproof—but only if they’re built for it. The key lies in their IP rating, how well they’re installed, and whether all parts (including cables, sockets, and plugs) are built to withstand outdoor conditions.

In the UK, where moisture and rain are almost always a factor, choosing IP44 or IP65-rated festoon lights is essential if you want reliable, safe, and long-lasting lighting.

Whether it’s a summer garden party or permanent pub terrace lighting, make sure your lights aren’t just beautiful—they’re built to brave the British weather.