Our pick: the Sea to Summit Ultra-Sil Pack Cover: four sizes for 15–95 liter packs, 2.0 to 4.6 ounces, cut without seams. Budget: Unigear Backpack Rain Cover. Biggest packs: Osprey Ultralight Raincover (XL to 110 liters). Most secure fit: Gregory Raincover.
Cover or liner? A cover keeps the pack itself dry, but rain can still get in between your back and the harness, Sea to Summit says. For a day of steady rain, add a pack liner or dry bags.
Buy the size that matches your pack’s volume in liters. Our fit table lines up every maker’s size chart, gaps included.
| Rain cover | Best for | Fits packs | Weight | Fabric | Price | |
|---|---|---|---|---|---|---|
| Sea to Summit Ultra-Sil Pack Cover | Best overall | 15–95 L (4 sizes) | 2.0–4.6 oz | 30D siliconized nylon, no seams | $$–$$$ | Check price |
| Unigear Backpack Rain Cover | Best budget | 10–70 L (5 sizes) | 3.6–4.9 oz (L–XXL) | 70D/210T nylon, 5,000 mm rating | $ | Check price |
| Osprey Ultralight Raincover | Best for the biggest packs | 30–110 L (3 sizes) | 4.0–4.9 oz | 40D recycled nylon, taped seams | $$–$$$ | Check price |
| Gregory Raincover | Best for a secure fit | Up to 80 L (3 sizes) | 3.0–4.8 oz | 70D polyester ripstop, taped seams | — | Check price |
| Deuter Raincover III | Best one-size cover | 45–90 L (1 size) | 4.6 oz | 70D polyamide, PU coating, taped seams | $$ | Check price |
| Kelty Raincover | Best for Kelty packs | 30–105 L (3 sizes) | 5.3 oz (L) | 70D polyester ripstop | $$ | Check price |
| Osprey Hi-Vis Raincover | Best for visibility | 10–35 L (2 sizes) | 3.9–5.5 oz | 100D × 210D recycled ripstop nylon | $$ | Check price |
| CamelBak Rain Cover (S/M) | Best for hydration packs | 16–25 L (1 size) | 2.1 oz | — | $ | Check price |
| Mountainsmith Backpack Raincover | Best in blaze orange | 15–60 L (3 sizes) | 2.5–4 oz | 70D sil-nylon, no seams | $–$$ | Check price |
Specs from each maker’s product page, October 2026 (Osprey: its pages as archived 2025–April 2026; osprey.com blocks scripted checks). Weights run smallest to largest size. “—” = not published, or (Gregory price) its US store was unreachable. Price bands at US list price: $ under $20 · $$ $20–45 · $$$ over $45.
How we chose
This guide has covered backpack rain covers since 2019. Our earlier editions described each cover from its maker’s specs, with no hands-on tests, and this update doesn’t claim any either. For this October 2026 update (edited by Brian Hamilton), we re-checked every pick on its maker’s own site.
- Five picks moved to their makers’ current versions: Kelty, Mountainsmith and both Osprey covers were redesigned, and CamelBak now sells only its small size in the US.
- We dropped the Joy Walker cover: it has no maker website, so we couldn’t confirm its sizes or specs anywhere but Amazon.
- We added the Gregory Raincover, which three of the five top-ranking rain cover reviews we read include.
Then we lined up every maker’s size chart to build the fit table. Where a maker doesn’t publish a spec, we show a dash, not a guess.
The best backpack rain covers
For most hiking and backpacking packs, start with the Sea to Summit, or the Unigear if price matters most. Osprey covers the biggest packs and Deuter fits 45 to 90 liters in one size.
1. Sea to Summit Ultra-Sil Pack Cover: Best overall
On this list since 2019 and still the best all-rounder: four sizes from 15 to 95 liters, 2.0 to 4.6 ounces. Sea to Summit cuts it without seams, so there are no stitch lines to leak.
The 30-denier Ultra-Sil fabric is siliconized nylon with a PU coating inside, rated above 2,000 mm. A keeper strap (S to L) pulls it tight across the harness, there’s a drain hole, and the stuff sack is attached so it can’t blow away.
Key specs: 2.0 / 3.0 / 4.0 / 4.6 oz (XS / S / M / L) · fits 15–30 / 30–50 / 50–70 / 70–95 L · 30D Ultra-Sil nylon · no seams · drain hole · $$–$$$
Pros
- Light in every size
- No seams to fail
- Keeper strap holds it across the harness
Cons
- Thinnest fabric here (30D)
- XS has no keeper strap
- Two price bands above the Unigear in the larger sizes
Skip it if: your pack is over 95 liters (get Osprey’s XL) or you want the cheapest cover that works (Unigear).
2. Unigear Backpack Rain Cover: Best budget
The lowest-priced cover here. Unigear rates its 70D/210T nylon at 5,000 mm and adds a drain grommet, a reflective logo, an elastic rim and two buckle straps that cross the back of the pack. It’s machine washable.
Five sizes, each spanning about 10 to 15 liters, run from S (10–20 L) to XXL (56–70 L). The chart also shows a 71–90 L XXXL that Unigear’s US store doesn’t sell.
Key specs: 3.6 / 4.6 / 4.9 oz (L / XL / XXL; S, M not published) · fits 10–20 / 21–35 / 36–45 / 46–55 / 56–70 L · 70D/210T nylon · 5,000 mm · drain grommet · $
Pros
- Lowest price band
- Two straps across the harness
- Five colors, including orange and fluorescent green
Cons
- Nothing over 70 L in the US store
- Its pages disagree on the range (15–90 L vs 10–90 L)
- 30-day replacement, not a lifetime warranty
Skip it if: your pack is over 70 liters.
3. Osprey Ultralight Raincover: Best for the biggest packs
All five top-ranking reviews we read include it, and its XL is the biggest cover here, for packs of 75 to 110 liters. Osprey makes it from recycled 40-denier nylon with a PFAS-free water repellent, tapes the seams and uses a draw cord. It packs into itself.
Our earlier editions described the previous version, with reflective strips and a blinker light. Osprey’s current page lists neither, so this card is on the new model’s specs.
Key specs: 4.0 / 4.4 / 4.9 oz (M / L / XL) · fits 30–50 / 50–75 / 75–110 L · 40D recycled nylon · taped seams · draw cord · $$–$$$
Pros
- XL fits packs up to 110 L
- Taped seams, PFAS-free fabric
- Osprey repairs its gear free, for any reason
Cons
- No size under 30 L
- No strap across the harness
- Medium weighs about 1 oz more than Sea to Summit’s S
Skip it if: your pack is under 30 liters. Osprey’s Hi-Vis Raincover (below) is the small one.
4. Gregory Raincover: Best for a secure fit
New in this update. We haven’t used this one ourselves; it’s here on its maker’s specs.
Gregory anchors its cover three ways: an elastic drawcord, hip-belt loops, and an adjustable hook that clips above the shoulder harness. It’s seam-taped 70D polyester ripstop (40% recycled), with a drain hole and an oversized reflective logo.
Key specs: 3.0 / 3.8 / 4.8 oz (86 / 109 / 136 g) · fits under 30 / 30–50 / 50–80 L · 70D polyester ripstop · taped seams · drain hole · hip-belt loops, harness hook
Pros
- Drawcord, hip-belt loops and harness hook
- Taped seams plus a drain hole
- A size for packs under 30 L
Cons
- Stops at 80 L
- Heavier than the Sea to Summit, size for size
- We could reach only Gregory’s European store
Skip it if: your pack is over 80 liters.
5. Deuter Raincover III: Best one-size cover
One size fits packs from 45 to 90 liters, so one cover can move between a weekend pack and an expedition pack. It’s the same Raincover III our earlier editions covered: 70-denier polyamide (nylon) with a PU coating, taped seams, reflective details and a drawcord.
For smaller packs, Deuter sells the Raincover I (20–35 L) and II (30–50 L).
Key specs: 4.6 oz (130 g) · fits 45–90 L · 70D polyamide, PU coating · taped seams · drawcord · lifetime warranty · $$
Pros
- One cover for 45–90 L packs
- PU coating and taped seams
- Lifetime warranty
Cons
- Drawcord only, no straps or loops
- Nothing over 90 L
- Deuter’s US store quoted 10–11 days for delivery
Skip it if: you own one pack. A fitted Sea to Summit or Osprey size spans a narrower range.
6. Kelty Raincover: Best for Kelty packs
Kelty’s sizes line up with its own packs: Medium (30–50 L) for an Asher 35, Large (55–75 L) for an Asher 65 or Trekker 65, and XL (80–105 L) for an Asher 85 or Glendale 85. A fully wrapped elastic cinch and hip-belt loops hold it on.
The current version is 70D polyester ripstop, which Kelty calls “fully waterproof fabric with C0 DWR”. Our earlier editions covered the previous two-size nylon cover. Kelty still lists it, but every size was sold out when we checked in September and again in October.
Key specs: 5.3 oz (L; other sizes not published) · fits 30–50 / 55–75 / 80–105 L · 70D polyester ripstop · hip-belt loops · stows in its own pocket · $$
Pros
- Sized to Kelty’s 35, 65 and 85 L packs
- Hip-belt loops plus a full elastic cinch
- XL fits up to 105 L
Cons
- Sold out at Kelty in every size
- No size for 51–54 L or 76–79 L packs
- Heaviest Large here
Skip it if: you need a cover this week. The Osprey Ultralight covers the same range.
Best rain covers for daypacks and visibility
Small packs need small covers, and anyone on roads or hunting-season trails benefits from color. These three fit daypacks and hydration packs; the Mountainsmith stretches to 60 liters.
7. Osprey Hi-Vis Raincover: Best for visibility
A bright cover with reflective print for daypacks, “whether you are moving fast on the trail or on your daily commute”, as Osprey puts it. A full wraparound attachment cinches it to the pack.
The fabric has the highest denier here, recycled 100D × 210D triple-ripstop nylon, seamless and coated “for water resistance”. That makes it heavy for its size. Our earlier editions described a previous version with a blinker light, which Osprey no longer lists.
Key specs: 3.9 / 5.5 oz (XS / SM) · fits 10–20 / 20–35 L · 100D × 210D recycled ripstop nylon · seamless · reflective print · $$
Pros
- Bright color and reflective print
- Highest-denier fabric on the list
- Sizes for small daypacks and commuter bags
Cons
- The SM outweighs Sea to Summit’s 95 L Large
- Rated for “water resistance”
- Nothing over 35 L
Skip it if: you count ounces. The CamelBak below weighs 2.1.
8. CamelBak Rain Cover (S/M): Best for hydration packs
Made for 16 to 25 liter hydration packs, at 60 grams (2.1 ounces), in bright yellow with reflective details. An elastic strap passes under your shoulder straps and closes with hook-and-loop, then a drawstring snugs the bottom.
CamelBak calls it “water resistant” and doesn’t list the fabric. Our earlier editions covered the M/L (25–38 L), which CamelBak’s US store no longer sells.
Key specs: 2.1 oz (60 g) · fits 16–25 L · bright yellow, reflective · strap with hook-and-loop, plus drawstring · $
Pros
- Only 2.1 oz
- Strap under the shoulder straps holds it on
- Bright yellow for daytime visibility
Cons
- One size, 16–25 L only
- No fabric or coating listed
- Rated “water resistant”
Skip it if: your pack is over 25 liters. Osprey’s Hi-Vis SM goes to 35.
9. Mountainsmith Backpack Raincover: Best in blaze orange
Our earlier buying guide’s tip still stands: in hunting season, blaze orange helps other people see you. Mountainsmith’s cover comes in Blaze Orange or Lemon Chrome yellow, and its 2026 redesign removes the seams.
It’s silicone-coated 70D × 190T nylon taffeta with a urethane backing, held on by elastic binding. Mountainsmith modestly says it will “help shed water”. Sizes match Mountainsmith’s own packs, and its Lumbar Pack Raincover suits our best hiking fanny packs.
Key specs: 2.5 / 2.9 / 4 oz (SM / MD / LG) · fits 15–25 / 30–45 / 45–60 L · 70D × 190T sil-nylon · no seams · elastic binding · $–$$
Pros
- Blaze Orange option
- New seam-free pattern
- 4 oz for a 60 L pack
Cons
- Nothing over 60 L, and no size for 26–29 L
- Elastic edge only, no strap
- Large in Blaze Orange was sold out when we checked
Skip it if: your pack is over 60 liters. Unigear’s orange runs to 70.
What size rain cover do you need?
One whose stated range includes your pack’s volume in liters. Find your pack’s size in the top row and read down. Where a pack sits exactly on a boundary, two sizes fit.
| Cover | 20 L | 30 L | 40 L | 50 L | 65 L | 75 L | 90 L | 105 L |
|---|---|---|---|---|---|---|---|---|
| Sea to Summit Ultra-Sil | XS | XS or S | S | S or M | M | L | L | — |
| Unigear | S | M | L | XL | XXL | XXXL* | XXXL* | — |
| Osprey Ultralight | — | M | M | M or L | L | L or XL | XL | XL |
| Gregory Raincover | Under 30 L | 30–50 L | 30–50 L | 30–50 or 50–80 L | 50–80 L | 50–80 L | — | — |
| Deuter Raincover | I | I or II | II | II or III | III | III | III | — |
| Kelty Raincover | — | M | M | M | L | L | XL | XL |
| Osprey Hi-Vis | XS or SM | SM | — | — | — | — | — | — |
| CamelBak Rain Cover | S/M | — | — | — | — | — | — | — |
| Mountainsmith | SM | MD | MD | LG | — | — | — | — |
From each maker’s size chart or product page, October 2026 (Osprey: archived 2025–April 2026). A size counts if your pack falls inside its stated range, end points included. *On Unigear’s chart, not in its US store. Deuter’s I and II are separate products.
Mind the gaps. Kelty has no size for a 51–54 or 76–79 liter pack, and Mountainsmith none for 26–29 liters. If your pack falls in a gap, pick another brand rather than squeezing into the smaller size.
Sea to Summit and Unigear both say to buy one size up if you carry gear on the outside of your pack, since a tent or pad strapped on adds bulk the liter figure doesn’t count.
A 22-liter daypack, for example, fits Sea to Summit’s XS, Unigear’s M, Osprey’s Hi-Vis SM, the CamelBak, Mountainsmith’s SM, Gregory’s under-30 size or Deuter’s Raincover I. Unsure of your pack’s size? See our guide to types of backpacks.
Did you know? Only two covers on this list fit packs over 95 liters: Osprey’s Ultralight XL, rated to 110 liters, and Kelty’s XL, rated to 105. Deuter’s Raincover III stops at 90 and Gregory’s biggest at 80.
Are backpack rain covers waterproof?
The fabric usually is, but a cover isn’t a sealed bag. Its back is open where it meets your back and shoulder straps, and Sea to Summit warns that “wind-driven rain can still enter through the space between your back and the harness”.
| Cover | What the maker promises | Seams | Drain hole |
|---|---|---|---|
| Sea to Summit Ultra-Sil | “durable, waterproof performance” | None | Yes |
| Unigear | “entirely waterproof”, 5,000 mm | — | Yes |
| Osprey Ultralight | “protected and dry” in downpours | Taped | — |
| Gregory Raincover | “Waterproof, seam-taped construction” | Taped | Yes |
| Deuter Raincover III | “Waterproof”; also “water-repellent” | Taped | — |
| Kelty Raincover | “Fully waterproof fabric” | — | — |
| Osprey Hi-Vis | “for water resistance” | None | — |
| CamelBak Rain Cover | “water resistant cover” | — | — |
| Mountainsmith | “help shed water” | None | — |
Quotes from each maker’s product page, October 2026 (Osprey: archived 2025–April 2026). “—” = the maker’s page doesn’t say.
What a 5,000 mm rating means: it’s a hydrostatic head, the height of a column of water a fabric holds back before it seeps through. Higher is more waterproof. Unigear rates its cover at 5,000 mm and Sea to Summit its Ultra-Sil fabric above 2,000 mm; the others don’t publish one.
Silicone or PU coating? Sea to Summit and Mountainsmith use silicone-coated nylon with polyurethane inside, and Deuter’s nylon is PU-coated. The bigger difference is seams: Sea to Summit and Mountainsmith cut them out, while Osprey, Gregory and Deuter tape theirs.
If an older cover starts to seep, a waterproofing spray can refresh it.
Rain cover or pack liner: do you need both?
For a few hours of showers, a cover is enough. For a day of steady rain, REI lists a cover, a liner and dry sacks as extra protection, because pack seams often aren’t sealed and even covered zippers “can let water sneak in eventually”.
| Rain cover | Pack liner | |
|---|---|---|
| Where it goes | Over the outside of the pack | Inside the main compartment |
| Keeps dry | The pack fabric, outside pockets and gear strapped on | Whatever is inside the liner |
| Water gets in | At the open back, between you and the harness (Sea to Summit) | To the pack and outside pockets, which “can get soaked eventually, making your load heavier” (REI) |
| Options | A fitted cover, or a trash bag with strap slits if you can stand it “flapping in the wind” (REI) | A trash-compactor bag, a purpose-made liner or several smaller plastic bags (REI) |
Sources: REI, Tips for Backpacking in the Rain (advice from REI’s Laura Evenson, whose Appalachian Trail thru-hike included 27 straight days of rain; read October 2026), and Sea to Summit’s pack cover FAQ, October 2026.
Our take: a cover for showers, both for wet trips. REI adds that, even with a cover or liner, your most vulnerable gear belongs in dry bags, especially a down sleeping bag. See our dry bag picks.
A cover alone does nothing if the pack goes underwater, as our earlier buying guide noted: it only protects the parts exposed to rain. On packrafting or kayak trips, pack the inside in dry bags.
How do backpack rain covers stay on?
Most grip the pack with an elastic rim or drawcord. What differs is what else holds them in wind:
- Drawstring or elastic only: Osprey Ultralight, Deuter, Osprey Hi-Vis and Mountainsmith.
- A strap across the harness: Sea to Summit’s keeper strap (S to L), Unigear’s two buckle straps and CamelBak’s hook-and-loop strap.
- Hip-belt loops: Gregory and Kelty. Gregory also clips a hook above the harness.
Whichever you choose, cinch it until the cover sits snug, with no loose fabric to catch the wind.
When don’t you need a backpack rain cover?
Check your pack first: REI notes that some packs come with one. Some ponchos are roomy enough to go over a pack, and several of our rain poncho picks do.
A cover is also redundant on a waterproof hiking backpack. And on a short hike in dry weather, a trash-compactor bag inside your day hiking backpack is a cheap backup.
I’ve been using the Osprey Ultralight Raincover for months now, and it’s been a lifesaver on my treks. Light and easy to pack!