8 Best Pack Covers And Dry Sacks For Backpacking In The Rain

Watching dark storm clouds roll over a distant ridge can trigger a sudden spike of anxiety if your dry gear isn’t actually secure. A soaked sleeping bag or drenched spare clothing can quickly transform an enjoyable weekend trek into a cold, miserable, and potentially dangerous ordeal. Choosing the right combination of pack covers and dry sacks ensures that your essential gear remains bone-dry, no matter how hard the skies open up.

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Pack Covers vs. Dry Sacks: Choosing Your System

Pack covers go on the outside of your backpack, while dry sacks go on the inside. A pack cover acts as your first shield, keeping the backpack itself from absorbing water, which can add several pounds of water weight to your shoulders. Dry sacks, on the other hand, guarantee that individual, critical items like down jackets and electronics stay completely dry even if water manages to penetrate the main pack body.

Relying solely on an external cover is risky in high winds or thick brush, where the cover can easily blow off, shift, or snag and tear. Conversely, using only dry sacks inside your pack means your backpack harness, padding, and fabric will get waterlogged during a downpour. This makes the pack heavy, soggy, and highly uncomfortable to wear for the remainder of the day.

The most reliable strategy for recreational backpackers is a hybrid system. Use a lightweight pack cover to keep the pack fabric dry, combined with individual dry sacks or a pack liner for your absolute must-dry sleep system and dry clothes. This dual layers of protection ensures you always have a dry sanctuary to climb into at the end of a wet day on the trail.

Understanding Waterproof Ratings and Fabric Durability

Look for hydrostatic head ratings, measured in millimeters (such as 2,000mm or 10,000mm), to understand how much water pressure a fabric can withstand before leaking. For backpacking rain covers, a rating of 1,500mm to 2,000mm is plenty for blocking falling rain. Dry sacks that might sit in pooled water or experience packing pressure benefit from higher ratings to prevent moisture from squeezing through the fibers.

Fabric durability is measured in Denier (D), which indicates the thickness and weight of the individual threads. Ultralight fabrics, usually 15D to 30D siliconized nylon, save valuable ounces in your pack but require more careful handling. Heavy-duty dry bags utilize 70D to 420D nylon with polyurethane coatings, making them highly resistant to punctures and abrasions at the cost of added weight.

Pack Cover – Sea to Summit Ultra-Sil Pack Cover

An external pack cover is your first line of defense against steady downpours. It wraps around the exterior of your backpack, preventing the harness, hip belt padding, and main compartment fabric from absorbing water and becoming sluggishly heavy. This keeps your overall carrying weight consistent throughout a rainy day on the trail.

The Sea to Summit Ultra-Sil Pack Cover strikes the ideal balance between weight and protection. Made from 30D siliconized Cordura, it is incredibly compact, packing down to the size of a tiny egg, yet it boasts a 2,000mm hydrostatic head to block heavy rain. The elasticized drawcord ensures a snug fit around the pack, preventing the wind from catching it like a sail.

Keep in mind that ultra-thin fabrics can snag on sharp branches if you frequently bushwhack off-trail. Ensure you choose the correct size based on your pack’s volume, keeping in mind that external gear like foam pads or water bottles will require you to size up.

• Best for: General backpacking, wet-weather trail hiking, weight-conscious hikers
• Sizes: XXS (10-15L) to XL (70-95L)
• Material: 30D Ultra-Sil Cordura nylon

This cover is perfect for hikers who stick to established trails and want a reliable, ultra-lightweight shield. It is not suitable for rugged bushwhackers or hunters who need heavy, abrasion-resistant fabrics to plow through dense, thorny underbrush.

Backpack Rain Cover – Gregory Pro Raincover

Standard pack covers can flap, shift, or pool water at the bottom if they do not fit securely. A premium, feature-rich cover solves this by offering dedicated attachment points that keep the cover locked tight to the pack harness even in high winds. This prevents the cover from ballooning or blowing away during exposed ridge walks.

The Gregory Pro Raincover is built for demanding mountain weather. It features a secure drawstring closure and a webbing strap that runs behind the harness, ensuring the cover stays locked in place during gusty ridge walks. The bottom panel includes a drain hole to prevent water from pooling if any moisture manages to seep down the back panel.

This cover is constructed from a heavier, more durable ripstop polyester than ultralight models, which adds a few ounces to your base weight. Its robust build means it handles scrapes against rocks and branches with ease, requiring very little babying on the trail.

• Best for: High-wind environments, rugged mountain terrain, heavy rain
• Sizes: 30-50L, 50-80L, 80-120L
• Material: 40D High-density ripstop polyester

This is the ideal choice for backpackers who prioritize security and durability over absolute weight savings, especially in exposed, windy alpine zones. It is overkill for casual weekend hikers who only expect light summer showers.

Dry Sack – Osprey Ultralight Dry Sack

Inside your pack, organization and water protection must go hand-in-hand. Roll-top dry sacks act as individual waterproof compartments, ensuring that even if water penetrates your pack cover, your core items remain completely dry. They also help organize gear by color, making it easy to find what you need in a hurry.

The Osprey Ultralight Dry Sack features a unique rectangular shape instead of the typical round bottom. This design allows the sacks to pack more efficiently into the corners of your backpack, eliminating wasted dead space. Made from 40D ripstop nylon, they offer excellent tear resistance while remaining light enough to carry multiple bags for gear organization.

The roll-top closure requires at least three tight folds to create a reliable waterproof seal. Because these bags are highly compressible, air can get trapped inside during closing; you must compress the air out before completing the final roll.

• Best for: Internal pack organization, clothing storage, food protection
• Sizes: 3L, 6L, 12L, 20L, 30L
• Material: 40D Siliconized ripstop nylon

This sack is perfect for organized hikers who want to maximize their internal pack volume with space-saving, rectangular gear storage. It is not designed for paddlesports or situations where the bag might face prolonged submersion.

Lightweight Dry Sack – Sea to Summit Ultra-Sil

When every ounce matters on a multi-day trek, heavy storage bags are out of the question. An ultralight dry sack provides the essential barrier against moisture without adding noticeable bulk or weight to your pack. This allows you to protect delicate items without sacrificing your lightweight packing goals.

The Sea to Summit Ultra-Sil Dry Sack is a classic choice for weight-conscious backpackers. Utilizing 30D siliconized Cordura nylon, it is incredibly slippery, making it easy to slide into a packed bag, and features a waterproof rating of 2,000mm. The reinforced, hypalon roll-top closure ensures a secure seal that will not wick moisture into the opening.

The thin fabric is semi-translucent, which is incredibly convenient for identifying contents without opening the bag. However, you must avoid packing sharp objects, like stoves or multi-tools, directly against the fabric without a protective sleeve.

• Best for: Ultralight backpacking, keeping sleeping bags dry, organizing clothing layers
• Sizes: 1.5L to 35L
• Material: 30D Ultra-Sil Cordura nylon

This is the ultimate option for long-distance hikers looking to minimize base weight without sacrificing moisture protection. It is not robust enough to be lashed to the outside of a pack or subjected to rough, external handling.

Compression Dry Sack – Sea to Summit eVent

Bulky items like sleeping bags and insulated jackets take up massive amounts of space inside a pack. A compression dry sack solves this by allowing you to squeeze out trapped air while keeping the contents fully sealed against moisture. This optimizes internal space while guaranteeing your sleeping gear stays dry.

The Sea to Summit eVent Compression Dry Sack uses a brilliant design featuring an air-permeable eVent fabric base. Instead of needing a purge valve, you simply roll down the top and compress the sack; air escapes through the bottom membrane, but water cannot get in. Four straps allow you to compress your gear into a rock-hard, space-saving bundle.

Do not over-tighten the compression straps to the point of straining the stitching, as this can degrade the waterproof seam tape over time. Because compressed gear becomes highly dense, it can create hard spots in your pack that might press uncomfortably against your back if packed poorly.

• Best for: Packing down sleeping bags, bulky fleece, and winter clothing
• Sizes: S (10L down to 3.3L) to XL (30L down to 10L)
• Material: 70D Nylon body with eVent fabric base

This is essential gear for cold-weather backpackers or those carrying lofty down sleeping bags in wet climates. It is unnecessary for hikers who use synthetic quilts that do not compress well or those using small, low-volume summer gear.

Heavy-Duty Dry Bag – Sea to Summit Big River

Some adventures require gear protection that goes far beyond light rain. For water-based travel, river crossings, or external pack lashing, you need a heavy-duty bag that can survive intense abrasion and temporary submersion. This ensures your most critical gear survives rough handling in extreme conditions.

The Sea to Summit Big River Dry Bag is built like a tank from rugged 420D ripstop nylon. It features heavy-duty lash loops on the sides, allowing you to securely strap the bag to the outside of your backpack, a kayak deck, or a packraft without fear of tearing the fabric. The white interior laminate makes finding small gear items at the bottom of the bag much easier in low light.

This level of durability comes with a weight penalty; it is significantly heavier than ultralight siliconized sacks. It is also stiffer to roll, requiring a bit more hand strength to achieve a tight, secure seal at the top closure.

• Best for: Packrafting, river crossings, lashing gear externally, rugged base camps
• Sizes: 5L to 65L
• Material: 420D TPU-laminated nylon

This bag is perfect for multi-sport adventurers who transition between backpacking, paddling, and rough travel. It is not suitable for traditional trail hikers looking to keep their pack weight as low as possible.

Durable Dry Sack – REI Co-op Durable Dry Sack

Mid-weight dry sacks provide a practical middle ground for hikers who want more durability than ultralight fabrics offer, but without the extreme weight of expedition-grade bags. They protect critical gear from punctures inside your pack while handling general trail abuse. This makes them a highly versatile and cost-effective choice.

The REI Co-op Durable Dry Sack offers exceptional value and ruggedness with its 100D ripstop nylon construction. It is tough enough to handle being set down on gravel or pine needles during camp setup without tearing. The bottom of the sack features a convenient grab handle, making it easy to pull out of a tightly packed backpack.

The rectangular bottom design helps it sit upright, which is helpful when packing or organizing your shelter. While highly water-resistant, keep in mind that the roll-top closure is not intended for submersion under water.

• Best for: General backpacking, budget-conscious hikers, base camping
• Sizes: 5L, 10L, 15L, 20L, 35L
• Material: 100D Ripstop nylon with TPU laminate

This is the perfect choice for recreational backpackers looking for a dependable, long-lasting dry sack at an accessible price point. It is not ideal for extreme ultralight enthusiasts who count every single gram.

Waterproof Pack Liner – Exped Fold Drybag Liner

Instead of managing several individual dry sacks, a pack liner turns your entire backpack’s main compartment into one large waterproof chamber. This simplified approach provides complete peace of mind with a single roll-top closure. It eliminates the need to pack and unpack multiple smaller bags inside your pack.

The Exped Fold Drybag Liner is specifically shaped to match the contours of a backpacking pack, featuring a wide opening and a tapered bottom. Made from lightweight, PU-coated nylon, it lines the interior of your pack, protecting everything inside from both external rain and leaky water bladders. The bright light-gray interior helps illuminate the depths of your pack, making gear retrieval simple.

Using a single liner means you lose some of the organizational benefits of individual color-coded dry sacks. You must also ensure that wet gear, like a damp tent fly, is stored outside of the liner to prevent it from soaking your dry sleeping bag.

• Best for: Simplified rain protection, lining entire internal frame packs
• Sizes: 50L, 80L, 140L
• Material: 70D Taffeta nylon, PU coated

This liner is ideal for hikers who want a foolproof, fast-to-pack waterproofing system for their entire gear loadout. It is not ideal for those who prefer highly organized, compartmentalized packing systems.

How to Pack Your Backpack for Maximum Rain Protection

Packing for wet weather is all about layering defense. Start by placing your pack liner inside the main compartment before loading any gear. Push your down sleeping bag and dry camp clothing to the very bottom, compressing them tightly to create a solid, stable base at the bottom of your pack.

Position your mid-weight items, like your stove and food bag, in the center, keeping them wrapped in their respective dry sacks if they contain sensitive items. Keep your wet items—such as a damp rain fly or muddy footprint—completely separate from the dry compartment, ideally stashing them in the external mesh pocket of your pack.

Finally, secure the top of your pack liner and deploy your external rain cover as soon as the first drops fall. This ensures that the pack fabric itself does not absorb water, keeping your total carrying weight low and protecting your harness system from becoming a cold sponge against your body.

Maintaining Your Waterproof Gear for Multi-Year Use

Waterproof coatings and seam tapes are highly effective but delicate over time. Never store your dry sacks or pack covers compressed, damp, or dirty after a trip. Hang them to air-dry completely in a shaded, well-ventilated area before rolling them loosely for long-term storage.

Dirt and trail oils can degrade the polyurethane coatings and adhesive seam tapes over time. Gently hand-wash your gear using a technical fabric cleaner or mild, scent-free soap, avoiding harsh detergents and never using a washing machine or dryer.

Inspect the inner seams annually for peeling tape or cracking coatings. If you notice leaks, you can easily repair minor punctures with a flexible urethane repair adhesive, or restore the external water-repellency (DWR) of your pack cover with a spray-on waterproofing treatment.

Conclusion

With the right combination of external covers and internal dry sacks, you can confidently hit the trail knowing that your gear is safe from the elements. Staying dry isn’t just about comfort—it is the foundation of a safe, successful backcountry adventure. Invest in a reliable protection system, and keep exploring, rain or shine.