Are Fly Rugs Waterproof?
It is the very common question every horse owner ask when choosing rug for the protection of their horse during summer. Fly rugs, also known as fly sheets, are designed primarily to protect horses from biting insects and UV rays not necessarily from rain. Yet, many riders confuse fly rugs, rain sheets, and turnout rugs, assuming all offer the same level of waterproof protection.
This confusion often leads to poor rug choices that affect a horse’s comfort, skin health, and temperature balance. A non-waterproof fly rug used in wet conditions can trap moisture, while an overly heavy waterproof rug in warm weather can cause overheating or irritation.
Understanding how fly rug materials, mesh designs, and waterproof coatings differ from true turnout fabrics is essential for making the right choice.
In this guide, we’ll explain how waterproof and breathable fly rugs differ, explore how they perform in real weather conditions, and help you decide when to use a fly rug, when to switch to a lightweight turnout rug, and how to choose the best option for your horse’s wellbeing especially for unpredictable UK summers.
What Is a Fly Rug?
A fly rug, often called a fly sheet, is a lightweight protective covering sheet designed to protect horses from flies, midges, and other biting insects during warmer months. These rugs are an essential part of every horse owner’s summer kit, helping to prevent irritation, rubbing, and stress caused by constant insect activity.
Unlike turnout rugs or rain sheets, a fly rug’s primary goal isn’t insulation or waterproofing it’s airflow and comfort. Most fly rugs are made from breathable mesh or fine polyester fabric, allowing heat to escape while creating a physical barrier against insects. Some advanced designs include built-in UV protection to help prevent coat bleaching and sunburn, particularly in lighter-skinned horses.
Because these rugs prioritise ventilation, they’re not waterproof. The open-weave mesh allows air to circulate freely and water to pass through easily. This ensures horses stay cool on hot days, but it also means a fly rug offers little protection from rain.
In short, a fly rug keeps your horse cool, comfortable, and bite-free in summer but it isn’t meant to replace a waterproof turnout rug when the weather turns wet.
Are Fly Rugs Waterproof?
The short answer is no most fly rugs are not waterproof. They’re designed for breathability, not rain protection. A traditional fly rug is made from lightweight mesh or fine polyester, materials chosen to maximise airflow and cooling during warm weather. These fabrics allow heat and moisture to escape but also let rainwater pass through, which means they don’t keep your horse dry in wet conditions.
Waterproof rugs, such as turnout rugs or rain sheets, work differently. They’re built with tightly woven or coated fabrics often polyester or nylon treated with a waterproof membrane that repel water while still allowing limited breathability. The goal of a turnout rug is to keep the horse dry and insulated, whereas the goal of a fly rug is to block insects and maintain airflow.
However, modern designs now include hybrid fly rugs, also known as fly combo rugs or fly rugs with rain protection. These feature a waterproof top section that covers the horse’s back and shoulders, combined with mesh panels along the sides for ventilation. They offer partial rain protection without overheating perfect for the unpredictable British summer.
In summary, standard fly rugs aren’t waterproof, but hybrid or combo fly rugs provide a balanced solution for light rain coverage and insect defence in one practical design.
Why Most Fly Rugs Are Not Waterproof
Most fly rugs aren’t waterproof for one simple reason: breathability. These rugs are made to keep horses cool in warm weather, and adding a waterproof coating would trap heat and moisture against the skin. When airflow is restricted, horses can quickly become hot, sweaty, and uncomfortable — especially in humid summer conditions.
Waterproof materials, such as coated polyester or nylon, don’t allow the same ventilation as open-weave mesh. Without consistent airflow, sweat and humidity build up, creating an ideal environment for skin irritation, heat rashes, or fungal infections. That’s why manufacturers typically avoid waterproofing standard fly rugs — it would defeat their primary purpose.
Seasonal conditions also matter. In UK summers, light showers often pass quickly, and most horses dry naturally once the rain stops. However, for areas with frequent drizzle or long turnout hours, hybrid fly rugs with waterproof tops can help protect the back and shoulders from short bursts of rain while maintaining airflow along the sides.
Simply put: keeping horses cool is more important than keeping them dry during fly season which is why most fly rugs remain intentionally non-waterproof.
Waterproof vs Water-Resistant Fly Rugs
Not all “rain protection” labels mean the same thing. When buying, it’s important to know the difference between waterproof, water-resistant, and showerproof fly rugs.
A waterproof fly rug (or more accurately, a hybrid fly rug) features a completely water-repellent top section, often made from ripstop polyester or nylon with a waterproof coating or membrane. This prevents rain from soaking through, keeping the horse’s back and shoulders dry.
Water-resistant or showerproof fly rugs, on the other hand, can handle light rain or drizzle but not prolonged wet weather. Their treated mesh or partially coated fabrics slow down water absorption but still let some moisture through.
Many leading brands now offer fly rugs with waterproof top panels and breathable mesh sides, combining rain protection with airflow. These are ideal for variable UK summers, offering the best of both worlds insect protection and light rain defence without overheating.
If you expect only short showers, a water-resistant or hybrid fly rug is ideal. For consistent rain, however, a fully waterproof turnout rug remains the smarter choice.
Practical Considerations & Buying Advice
When to Use a Waterproof Fly Rug
A waterproof fly rug is most effective for horses turned out in light summer rain, unpredictable weather, or for those with sensitive skin prone to irritation from both insects and moisture. In such cases, a standard mesh fly rug might allow too much dampness, while a full turnout rug could be unnecessarily heavy and warm.
In the UK’s changeable climate where sunshine often gives way to passing showers a hybrid fly rug featuring a waterproof top and breathable mesh sides offers excellent versatility. It protects the horse’s back and shoulders from rain while ensuring airflow along the flanks to prevent sweating.
Waterprooof Rugs also helps minimises rubbing and chafing for horses with fine coats or existing skin conditions. During prolonged rain or cooler weather, switch to a lightweight turnout rug, or pair a fly rug with a thin rain sheet for flexible coverage. All you have to do is to protect your horse from any type of skin infection or damage. For that purpose you will have to choose rugs or any other equipments carefully. For other equipments like halters, bridles, saddles or saddle pads you can also search about them or explore our guide of horse tack and gear.
In short, waterproof fly rugs are a smart choice for the UK’s unpredictable summers, helping horses stay dry, cool, and comfortable through quick weather changes.
Features to Look for in a Waterproof Fly Rug
- Waterproof top section – repels rain and keeps critical areas dry.
- Breathable mesh sides – allow ventilation to prevent overheating.
- UV protection – shields against harmful sun rays and coat fading.
- Detachable neck cover – adds flexibility for changing weather.
- Secure belly and leg straps – prevent slipping during turnout.
| Feature | Standard Fly Rug | Hybrid Fly Rug | Turnout Rug |
|---|---|---|---|
| Insect Protection | ✅ Excellent | ✅ Excellent | ⚪ Moderate |
| Waterproofing | ⚪ None | ✅ Partial (Top Only) | ✅ Full |
| Breathability | ✅ High | ✅ Good | ⚪ Moderate |
| UV Protection | ✅ Often | ✅ Often | ⚪ Optional |
| Best For | Hot, dry days | Light rain, mild weather | Prolonged wet or cold |
Common Materials Used in Fly Rugs
- Polyester mesh – durable, airy, and quick-drying; the most widely used.
- Nylon mesh – smooth and gentle, perfect for sensitive-skinned horses.
- PVC-coated mesh – adds slight rigidity and minimal water resistance but reduces breathability.
When waterproof coatings (like polyurethane or DWR finishes) are applied, the fabric becomes firmer and slightly less flexible. While this improves rain resistance, it can limit airflow.
Innovations such as Coolmax linings for moisture control and antibacterial mesh to reduce odour and irritation are now common in premium designs. For waterproof options, ripstop polyester tops combined with mesh sides deliver the best mix of durability, airflow, and weather protection.
How to Maintain a Fly Rug’s Water Resistance
To extend your rug’s lifespan, wash it gently using mild or specialist rug detergent, avoiding harsh chemicals that can strip coatings. Always air-dry naturally; heat can damage waterproof membranes.
Reapply protection with treatments like Nikwax Rug Proof or Fabsil when water starts soaking through. Store your rug clean and dry, folded neatly to prevent mould or fabric fatigue. Regularly inspect seams, straps, and coatings early repairs keep your rug performing effectively throughout the season.
Signs You’re Using the Wrong Rug
Your horse’s behaviour often tells you when a rug isn’t right. Watch for signs such as sweating, damp patches, rubbing, or restlessness. Behavioural cues tail swishing, rolling, or constant shifting usually mean discomfort or overheating.
Switch to lighter fly sheets in warm weather, and opt for turnout rugs when rain is prolonged or temperatures drop. Adjusting rugs seasonally keeps your horse comfortable, healthy, and happy outdoors.
Best Waterproof Fly Rugs for UK Horse Owners
- Weatherbeeta: Known for strength and durability, featuring waterproof tops and UV-protective mesh sides.
- Horseware (Rambo & Amigo ranges): Premium fit and quality with flexible neck options.
- Shires Equestrian: Excellent value for everyday turnout without compromising comfort.
- Criterion UK: Focused on practical design, comfort, and adaptability — built specifically for UK equestrian weather.
While budget options can work short-term, premium waterproof fly rugs offer better fit, durability, and consistent comfort a wise investment for long-term use.
FAQs
Can a fly rug be used in the rain?
Yes, but only if it’s a hybrid or waterproof-top style. Standard mesh fly rugs aren’t suited for wet weather.
What’s the difference between a fly rug and a turnout rug?
A fly rug protects from insects and sun using breathable mesh, while a turnout rug is insulated and fully waterproof for cold or wet weather.
Can I waterproof a fly rug myself?
You can use waterproofing sprays, but they reduce breathability and are not a lasting fix.
Are there waterproof fly rugs for ponies?
Yes, brands like Shires, Weatherbeeta, and Criterion UK offer adjustable pony-sized designs.
Should my horse wear a fly rug overnight?
Yes, if insects are active and nights are mild. Avoid use during rain or cold conditions.
Do waterproof fly rugs affect airflow or cause sweating?
Fully coated rugs might, but hybrid rugs with mesh sides maintain balanced ventilation.
What’s the best fly rug for the British summer?
A hybrid waterproof fly rug it offers insect protection, UV defence, and light rain coverage ideal for UK weather.
Conclusion
Most fly rugs aren’t waterproof but modern hybrid designs now provide smart protection against light rain, sun, and insects. The key lies in balance: breathability, comfort, and reliable weather resistance.
For UK horse owners, investing in a quality hybrid fly rug means year-round practicality. Designed for British climates, these rugs keep horses cool, dry, and comfortable whatever the weather brings.