Choosing a tent: shape, weight, and what waterproof actually means

Three shapes cover the pool: 36 tunnels, 30 domes and 17 semi-freestanding tents. Each is a structural answer to the same problem — holding fabric off your face while the wind tries to lay it flat — and each has a cost you pay elsewhere.

Tunnel

Two or three hoops set parallel, like the ribs of a boat. No poles cross, so a tunnel gives the most usable floor and headroom for the least weight: the walls rise steeply and stay that way end to end. It is the shape for two people who want to sit up at once.

The cost is that a tunnel is not a tent until it is pegged — nothing holds the hoops upright along its length except the tension between the two ends. It also has a direction. The narrow end goes into the prevailing wind, so the air runs over the hoops the way it runs over a wing. Pitched broadside in a gale, the wind pushes on the largest panel it can find, the hoops flex sideways, and poles break. On an exposed pitch that is the whole design.

Dome

Two poles crossing at the apex, sometimes more. The crossings brace each other, so a dome stands on its own and holds its shape whichever way the wind arrives. It has no wrong orientation, which matters on a plateau where the wind swings round overnight. You pay in pole weight, and in curved walls that fall away at head and foot, so a dome feels smaller inside than a tunnel of the same floor area.

Semi-freestanding

A hubbed pole assembly holds the head end up on its own and the foot tapers to one or two pegs. Most light one-person tents use it: the foot is where you need least room, so the taper is weight saved for nothing. The compromise is small and real — you must get two pegs in somewhere.

Freestanding means the tent holds its shape with no pegs in the ground. It does not mean it stays where you left it: an unpegged freestanding tent in a gust is a kite, and all of them still need their guylines out in real weather. What it buys is the ability to pitch where a peg will not go. If your answer to the ground question in the finder is rocky, it goes to the top of the list.

That situation is narrower than the marketing suggests and completely decisive when you are in it. Slabby rock, gravel, hardpan, frozen ground, and the wooden platforms some parks oblige you to use: a peg either bounces out or is forbidden. A freestanding tent goes up, and you anchor it with rocks on the loops, your pack and full bottles in the corners, or the platform's own tie-down rings. A non-freestanding tent up there needs cord and patience, and in the dark, more of both.

Flysheets here run from 1,200 mm to 5,000 mm hydrostatic head, median 2,000 mm. The test explains the limits of the figure. A piece of fabric is clamped under a column of water, which is raised until the first drops appear underneath. The height of that column in millimetres is the hydrostatic head — how much pressure a new, clean, flat sample resists in a laboratory.

A higher number is not simply better. Rain exerts very little pressure on a taut flysheet, so around 1,500 mm already keeps it out; figures above that buy margin against age, dirt and abrasion rather than against heavier weather. Head is bought with coating, and coating is weight — a 5,000 mm fly is usually a thicker polyurethane layer on heavier cloth. It also breathes less, and a fly that breathes less condenses more inside, which produces exactly the damp night people blame on a leak.

Floors are rated higher than flies on purpose, because the test there is pressure rather than rain: a kneeling adult presses their weight onto a small patch of fabric in wet ground. In practice tents leak at seams, at zips, and wherever the inner touches a wet fly — almost never through the middle of a panel. A well-pitched 1,500 mm tent stays drier than a slack 5,000 mm one. Treat the figure as a floor to clear, not a score to maximise.

The labels mislead, because they sound like temperature ratings. A tent does not keep you warm in any useful sense — it keeps wind and rain off, and the bag and pad do the rest. What separates three-season from four-season is snow load and ventilation.

• Snow load. A four-season tent has more poles, more crossings and steeper walls, so snow slides off instead of settling. Wet snow is heavy, and a three-season tent left under it overnight can be flattened with you inside.
• Ventilation. Three-season tents use large mesh panels for airflow. Four-season tents replace most of that mesh with solid fabric, because spindrift — fine, wind-driven snow — passes straight through mesh and fills the tent.
• Wind. Four-season designs carry the extra guying points and stiffer poles that sustained wind needs, which is why they overlap with the tents people buy for exposed ridges rather than for snow.

Both trades cut the other way. A four-season tent in July is a greenhouse you carried extra weight for, and a three-season tent is entirely usable well below freezing on a clear, still night. So the rule is about weather, not the thermometer: expect falling or blowing snow, or sustained wind on open ground, and buy four-season; expect cold and rain, and three-season is the right tool and the lighter one. Temperature is a question for the bag and pad — that is staying warm at night .

Tents here have one door or two. Solo, one is fine and a second is weight. For two people the second door is worth far more than it looks on a spec sheet, and it is the thing most often cut to save weight and regretted for years.

With one door, somebody sleeps on the inside. That person cannot get out at three in the morning without climbing over the other, and in a tent low enough to be light there is no graceful way to do it. Both sets of wet boots share one vestibule. With two doors each of you has an exit and a porch, wet kit stays away from dry, and opening both sides gives cross-ventilation.

Capacity flatters in the same way. This catalogue sleeps one to three, and those numbers are measurements rather than promises. "Two-person" means the floor is wide enough for two pads side by side, touching, with the packs left outside. If you want a pack inside, or you are two broad adults, or one of you moves in their sleep, the honest answer is a three-person tent.

Packed weights run 540 g to 4,200 g, median 1,740 g. That 3.7 kg spread between the ends of the pool is more than separates any two bags or pads here, which makes the tent the biggest lever on what your loaded pack weighs — see base weight and cutting weight .

Packed volume is the figure people forget, and it often decides more. Tents here take 2.5 to 13 litres; packs run 27 to 80 litres, median 58. A 13-litre tent eats roughly a fifth of a median pack before any bag, pad, food or water goes in. If the pack is already chosen, volume decides whether the kit fits at all, and no amount of careful packing recovers ten litres.

Prices run €130 to €1,250, median €450. The money buys, in order: a pitch that holds in wind, seam tape that stays stuck, lighter poles, then lighter fabric of the same strength. The last is where the top of the range goes — sub-kilogram tents cost what they cost because thin, strong, waterproof cloth is expensive, not because they shelter you better. The pool is at all 83 tents .

Work through it in this order — each answer removes more of the pool than the one after it. If the bag, pad and pack are still to buy too, buy all four as a set: how to choose a backpacking kit explains why.

1. Snow, or snow blowing about? Four-season. Otherwise three-season, and save the weight.
2. Rock, hardpan or wooden platforms? Freestanding, or semi-freestanding at the least.
3. Exposed, with wind from one reliable direction? A tunnel, nose into it. Wind from anywhere? A dome.
4. Two of you? Two doors, and check the floor width against your pads rather than the label.
5. Only then sort what is left by packed weight and packed volume, and see what the budget reaches.