In winter, the nights are longer, darker. All the more time for your outdoor sleepover! A winter adventure – whether a multi-day trip or a microadventure – can be a refreshing antidote to winter blues. This guide runs through what you need to bivvy in winter and how to stay warm.
Our guide to bivvying in the winter
- Can you bivvy in winter?
- How do you keep your bivvy warm in winter?
- What kit do you need for winter bivvying?
- How to set up your winter bivvy
Can you bivvy in winter?
Yes! When you bivvy in winter, you don’t need to share the stars. The outdoors is all yours. The Milky Way, the planets, the birdsong, and the silence. You can take winter in from the ultimate cosiness of your sleeping bag. You can do it, all it takes is a little more preparation.
How do you keep your bivvy warm in winter?
If you have already bivvied in the summer you will be relieved to know the same principles apply. You just need to take it to the next level.
- Prevent heatloss through the ground
- Use the layering system
- Eat and drink to fuel your body
- Protect your extremities
- Keep your sleeping bag dry.
There are four main ways in which you lose heat while bivvying in the winter: convection, conduction, evaporation and respiration.
Convection
Convection is when that lovely warm air next to your body really wants to move to the cold air outside your bivvy. The solution? Trap it!
Pull in the drawcords on your sleeping bag and on your windproof, waterproof bivvy. Wear breathable, warm base layers (we like Merino) and socks and a woolly hat to trap air next to your skin.
Conduction
Keeping your kit dry and clean is vital. Not only does wet kit conduct heat away from your body more quickly, but your down jacket and sleeping bag won’t keep you as warm if they’re damp and dirty. A dry bag will never go amiss. And if you’re sure you’re going to be sleeping out in the rain, a synthetic fill sleeping bag might be a safer bet than down due to its performance in both wet and dry conditions (the weight penalty is worth it!).
In winter especially, the ground will also conduct heat away from you. A thick, but packable insulated sleeping mat, like the CloudBase, is essential not only for comfort but also for warmth. For extra insulation use a closed cell foam mat underneath.
Evaporation
Evaporation very effective at getting rid of heat. This is great when it’s a warm, sunny day and we sweat to cool down. But this isn’t so great when you’re bivvying in the dead of winter. In fact, the body can lose up to 350ml of water during an 8-hour sleep. To prevent heat loss through evaporation, prevent as much environmental moisture as possible from getting into your sleep system. Put simply, don’t let the snow in. And to prevent extensive sweating overnight, try not to get in your bivvy cold in case you later overheat, sweat and cool down.
Respiration
It might seem tempting to snuggle up inside your sleeping bag to keep your face out from the cold. However, the moisture in your breath will condense and cause damp patches. If your sleeping bag has a down fill, this will negatively affect its insulating properties. And make you colder. What to do instead? Buy a beanie and breathe outside your bivvy.
What kit do you need for winter bivvying?
Our packing list for a winter sleepout includes:
- Basic sleep system
- Sleeping mat – we recommend a thicker, inflatable sleeping mat for maximum insulation and comfort
- Sleeping bag – highly lofted sleeping bag suitable with a comfort rating suitable for the outdoor temperature you’re expecting, like the AlpineDream
- Bivvy bag – windproof, waterproof and extra-large for keeping your winter sleeping bag, you and your kit dry
- Camping pillow (or a dry bag!)
- Clothes and accessories
- Merino base layers
- A woolly hat and socks
- (Plus all the gear you were walking in)
- Handy essentials
- Headtorch for navigating your campsite in the dark
- Camping stove to make a hot drink or some porridge in the morning
- Bottle you can fill with hot water to warm up your sleeping bag
- Lightweight tarp in case it rains, like the Rig
How to set up your winter bivvy
- Location - staying warm on a frosty hillside bivvy is also about location. Hot air rises – so dropping down a few metres could make you just a smidge colder. On the other hand, being very exposed at the highest point of a hill will steal all your body heat quicker than you say “hot water bottle”.
- Warm up before you snuggle up - Make sure you’re warmed up before you get in your bag. This could be as simple as eating a hearty meal or doing some star jumps before turning in for the night. That way your sleeping bag can retain your hard-earned heat all night.
- Keep your kit dry - Take advantage of your toasty sleeping bag for warming up extra kit. Don’t want to defrost your boots in the morning? Wrap them in an inside-out dry bag and shove them at the bottom of your bivvy bag. And keep your gloves and woolly hat inside the bag for when you need them first thing. Dry kit is warm kit.
- Multi-day hangout - If you’re on a multi-day trip, it’s essential that you dry out your bivvy in between sleeps. In the coldest of conditions, frost could form even on the inside of your bivvy bag. Turn it out, and hang it out to try while you’re hanging out at breakfast.
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