How do you stay warm in a tent on a single-digit night?

Most campers pack for the daytime forecast and then sleep through the overnight minimum, which is a different number entirely. Spring inland is the trap: the Bureau of Meteorology's long record for Stanthorpe, on the Granite Belt beside Girraween National Park, puts the mean September minimum at 5.2 degrees across 82 years of observations, while the same week on the coast is mild enough to eat dinner outside in a shirt. Knowing how to stay warm in a tent at that temperature is not about buying a warmer sleeping bag. It is about the order in which heat leaves you, which is the opposite of the order most people pack in.

How cold does it actually get inland in spring?

Cold enough to matter, and consistently enough that you can plan for it instead of gambling. Alongside Stanthorpe's 5.2 degrees in September, the Bureau's station at Applethorpe records a mean September minimum of 5.8 degrees, and across the border in the Northern Tablelands, Armidale Airport sits at 4.8 degrees and Glen Innes at 4.2. Those are means, which means half the nights are colder. October only lifts them to between 7.3 and 9.1 degrees. The relevant threshold is not freezing: healthdirect, the Australian government health service, notes that hypothermia can develop from exposure to air below 10 degrees for a prolonged period, and a night in a tent is a prolonged period by any reading. Single digits are not an edge case on the Granite Belt in spring. They are the average.

Mean daily minimum in degrees Celsius, from each station's long-term record.

Why does your sleeping bag rating not match how you slept?

Because the number on the label is usually not the number you should be reading. Sleeping bags sold in Australia are commonly rated to the European standard EN 13537, since replaced by ISO 23537, which publishes three temperatures, not one. Comfort is the temperature at which a standard female can expect to sleep comfortably in a relaxed position. Lower limit is the temperature at which a standard male, curled up, is in thermal equilibrium and just not feeling cold. Extreme is the minimum temperature at which a standard female can remain for six hours without risk of death from hypothermia. Retail listings often headline the limit or the extreme figure, because it is the larger-sounding one, and a bag advertised at minus five can have a comfort rating close to two degrees. One further caveat keeps that honest: the standard tests the bag with an insulating mat underneath, inside a tent, with base layers, socks and a hat. Take any of those away and the tested number no longer describes your night. The mat is the one the standard assumes and most campers skip, and there is a reason it matters more than the bag.

What actually takes your heat overnight?

The ground, and it is not close. Lying down puts most of your body in direct contact with a surface that has been losing heat since sunset, and the insulation in the bag underneath you is crushed flat by your own weight. The mechanism is conduction: your body is warmer than the ground, they are touching, and heat moves from one to the other all night. Down or synthetic fill only insulates while it is lofted, and the fill under your hips and shoulders is compressed to nothing before you fall asleep. That is the whole reason a mat is not a comfort item. Loft above you traps air; the loft below you has already been squashed and is doing nothing. The number that measures how well a mat resists that loss is R-value, and we have covered how to read it, and which mattress types earn which figure, in a separate guide on sleeping well in a tent. This article assumes you have picked that number and deals with everything stacked around it.

How to stay warm in a tent: what order do the layers go in?

Build it in this order, because each layer only works if the one under it exists: something insulating directly on the tent floor, your mat on top of that, then the bag, then what you wear inside it. On cold, compacted ground the first layer is a closed-cell foam mat or even a folded picnic blanket, and its job is to stop the mat itself from sitting against chilled ground. The mat is where the money goes. The Often deluxe self-inflating mattress, $189, has a listed weight of 5.4 kg and self-inflates, which matters at the end of a cold drive more than it does in a showroom, and the auto-inflatable double pad, $139, at 3.3 kg, covers two people on one surface with no gap between them to leak heat. Then dress for the bag rather than the campsite: dry base layers, socks that have not been walked in, and a beanie, because the standard assumed all three when it measured your bag.

Notice what is not on that list. No extra blanket thrown over the top, which adds weight and very little warmth, and no bundled jumper standing in for a pillow, which loses its shape by midnight. And one honest limit on the products above: a thicker mat raises you further off the floor, which helps with cold and hurts in a small tent where headroom and floor space are already the constraint. On a two-person site with a low-profile tent, the double pad wins on floor plan rather than on warmth: one surface for two people leaves no cold gap down the middle, and it occupies less of the tent floor than two singles pushed together.

Does where you pitch the tent change the temperature?

By several degrees, for free, and it is the cheapest decision on this page. Cold air is denser than warm air, so overnight it drains downhill and pools in the lowest ground on the site. That is the same hollow that collects water when it rains. The creek flat that looks idyllic at four in the afternoon is the coldest ground on the site at four in the morning. Pitch a little higher than the lowest point, put something solid between you and the prevailing wind, and orient the tent so the first sun of the morning lands on it, since a tent in shade at seven stays cold for another two hours. None of this requires equipment. It requires walking the site once before you unpack, which is the step people skip because the car is already stopped.

Why do you wake up damp, and does that make you colder?

Yes, and the cause is usually your own breathing, not rain. Warm, humid air from your breathing moves outward until it meets the fly, which is cold because the air outside is cold, and the water it was carrying condenses on the underside of that fabric. Damp bedding conducts heat away far faster than dry bedding, so a condensation problem becomes a warmth problem by about three in the morning. The fix is counterintuitive on a cold night: open the vents rather than sealing everything shut, because the air inside the tent is almost always more humid than the air outside, and replacing it with drier air is what stops the drip. Pitch the fly taut so there is a real air gap against the inner wall, open opposing vents so the air crosses instead of sitting, and keep wet boots and wet clothing in the vestibule instead of beside your head.

What should you fix first tonight?

Work upward from the ground, because that is the order in which the fixes pay. If you own one warm thing and it is a bag, the mat is what changes the night, not a warmer bag. If you own a good mat and still woke cold, add the layer under it and check the comfort rating rather than the headline number on the bag. If both are sorted, move the tent: uphill of the lowest ground, out of the wind, facing the morning sun. And open the vents before you sleep, not after you wake up damp. Two of those four cost nothing and are decided before you unpack. The full range of mats, with listed weights on every product page, is in the mattress collection.