Quick Answer: If your sauna lives outdoors year-round, a cover is cheap insurance against the two things that actually degrade cedar and hardware — UV and standing moisture. For a square cabin, a universal polyester cover like Xmatch’s (roughly $50–$90, sized for 1–4 person units) is the simplest fit; for a barrel sauna, a fitted marine-canvas “rain jacket” like Almost Heaven’s (roughly $200–$600 depending on retailer and size) sheds water off the curve the way a flat tarp can’t; and if you want an exact match to a custom or oversized build, a made-to-measure Sunbrella marine-canvas cover (from about $250) is the premium route. Skip covering a wood-burning unit with the chimney installed unless the cover has a cutout for it.
Most sauna buying guides stop at the heater and the wood species and never mention what happens to either one after a winter of exposure. If your barrel or cabin sits outside — which is the default for anything in our best barrel sauna or best outdoor sauna roundups — the cover is the accessory that actually protects the investment, not just an add-on.
Sauna covers at a glance
| Cover type | Best for | Material | Price |
|---|---|---|---|
| Xmatch Outdoor Sauna Cover | Square/cabin saunas, budget | 210T Oxford polyester | ~$50–$90 |
| Almost Heaven Barrel Rain Jacket | Barrel saunas | Marine-grade canvas | ~$200–$600 |
| Custom Sunbrella marine cover | Non-standard or oversized builds | Sunbrella acrylic marine canvas | ~$250+ |
| Generic waterproof tarp/cover | Temporary or seasonal use | PVC/vinyl | ~$25–$50 |
Why a cover matters more than it looks like it should
The visible damage — graying wood — has a specific cause. Sunlight breaks down lignin, the natural compound that binds wood fibers together, and as it degrades a thin gray layer roughly 0.003 to 0.01 inch thick forms on the exposed surface, made mostly of the leach-resistant cellulose that’s left behind once the lignin is gone (per wood-weathering research on UV degradation). That’s a slow, cosmetic process on its own — the bigger issue is what comes with it: once lignin at the surface breaks down, the wood underneath becomes more absorbent, and water exposure that used to bead off starts soaking in instead. That’s the combination — UV first, moisture second — that eventually warps staves and loosens joinery on an uncovered barrel or cabin.
Almost Heaven’s own care guidance backs this up directly: for a sauna that isn’t under a covered patio or pergola, the brand recommends either a fitted cover or, at minimum, a tarp strapped down and removed before each session — specifically to keep water and snow from sitting on the structure and to cut down UV exposure on days it’s not in use. That’s a sauna manufacturer telling its own customers to buy a cover, not a listicle padding out a page.
1. Xmatch Outdoor Sauna Cover — best for cabin saunas
Xmatch Outdoor Sauna Cover
- Sold in 1-person, 2-person and 4-person sizes to match common infrared cabin footprints rather than a one-size guess.
- 210T polyester is woven, water-resistant fabric — lighter and easier to fit over a square or slightly peaked cabin roof than stiff vinyl.
- Straightforward to remove and refit each session, which matters if you're covering and uncovering a home cabin regularly instead of leaving it outdoors seasonally.
Try Prime free for 30 days — start your free trial and get a cover on the doorstep before the next storm rolls through your yard.
This is the right starting point for anyone with a square or lightly-peaked home sauna or outdoor infrared cabin — flat panel walls are exactly what a generic sized cover is cut for, and you’re not paying for a fitted curve you don’t need.
2. Almost Heaven Barrel Sauna Rain Jacket — best for barrel saunas
Almost Heaven Barrel Sauna Rain Jacket
- Cut to the barrel's curve and secured with bungees, so it sheds water off the round roof instead of pooling like a flat tarp would.
- UV-resistant marine canvas, available in tan, navy and charcoal — built for the same year-round sun exposure as a boat cover.
- Does not fit wood-burning barrels with an installed chimney — there's no pipe cutout, so electric barrel owners are the intended fit.
If you own one of the barrels in our best barrel sauna guide, this is the shape-matched option — Almost Heaven’s Audra canopy model shields the door with a built-in porch overhang, but every barrel without that overhang is fully exposed on top, which is exactly what a fitted rain jacket covers.
3. Custom Sunbrella marine-canvas cover — best for a precise fit
For anything outside standard barrel or cabin dimensions — a custom-built structure, an oversized group barrel, or a shape a generic cover doesn’t fit — made-to-order shops like ALCO and SaunaCovers.com build covers to your exact measurements out of heavy-duty vinyl or Sunbrella marine canvas, the same acrylic fabric used on boat covers and rated for years of continuous sun. Laguna Covers, for example, prices a Sunbrella barrel sauna cover with a 10-year warranted marine canvas at around $250. It costs more than a universal cover and takes longer to arrive since it’s made to order, but it’s the option that won’t leave a gap flapping in the wind on a non-standard build.
4. Generic waterproof tarp/cover — best for occasional or seasonal use
Generic Waterproof Outdoor Cover
- The cheapest way to stop standing water and snow load if the sauna only needs protection for an off-season stretch.
- PVC doesn't breathe the way woven Oxford polyester or marine canvas does — strap it loosely and pull it off on dry days rather than sealing it tight.
- Expect a shorter lifespan under constant sun than a purpose-built sauna cover — this is the seasonal or backup option, not the year-round one.
If you’re mothballing a sauna for a season — moving, renovating the yard, or waiting to install a permanent cover — a basic tarp beats leaving the structure fully exposed. Just don’t expect PVC to match the multi-year UV life of marine canvas.
The bottom line
For a square or cabin-style sauna, an Xmatch-style universal cover at $50–$90 is the simple, correctly-sized answer. For a barrel sauna, a fitted marine-canvas rain jacket like Almost Heaven’s ($200–$600) sheds water off the curve the way a flat cover can’t. If your build is non-standard, a custom Sunbrella marine-canvas cover from about $250 gets you an exact fit. And if you just need to protect the structure for a season, a generic waterproof tarp ($25–$50) is a legitimate stopgap — just don’t expect it to last as long as purpose-built canvas. Whichever you buy, remember the wood-burning caveat: a fitted cover without a chimney cutout doesn’t work on an active wood-fired barrel.
Next steps: our best sauna accessories guide covers the rest of the gear worth buying once the sauna itself is set up, best barrel sauna and best outdoor sauna cover the structures a cover like this protects, and best cedar sauna explains why the wood species you chose matters even more once you know what UV and moisture do to it uncovered.