Watch the weather IN the location where you’re going and BE PREPARED. Then Pack accordingly.
Know how far you need to hike from the cars - can you bring everything in your backpack or will you need to do multiple trips
Eat and drink a lot - this is one time when snacking often is good; as it keeps your internal furnace constantly going
Layering is key! Multiple thin layers is often better than one massive jacket. You can peel off pieces if you’re active and start to warm up
A down jacket is the warmest - but if there is wind then you’ll also want a shell over tope of that
Long johns, thermajohns, or a thin base layer is great
Consider hiking boots, cowboy boots or something with higher coverage than tennis shoes will keep your feet warmer
Multiple layers of (non-cotton) socks are also best to keep your toes warm. The best is a thin pair combined with a warmer wool or merino wool sock. In really cold conditions wrapping your socks or at least your toes in Saran Wrap does wonders
Gloves - a thinner pair may be helpful when preparing dinner and setting up and taking down camp as you’ll need more dexterity
Hats that cover your ears
Handwarmers help as an extra precaution - you can buy a case of 40 online.
Look for something that may give you a natural wind block
If there is snow or ice possible then avoid setting up under a tree which may have limbs break off from the weight of the ice or snow
Team up and share a tent with another scout or if tenting alone consider a small 1-man tent with a full fly
The body heat of more than one person in a tents helps keep it warmer
Always keep the vent open in the top of your tent if it doesn’t have any existing mesh that will allow some air to escape - this is critical to minimize the buildup of condensation
Quality down sleeping bag Rated for the temps is key. There are 2 types of temperature rating standards out there - the typical one means that you can ‘survive and won’t die’ in a bag rated at that temperature. You want to look for bags that have a ‘comfort’ rating. You should generally look for a bag that is rated for 20-30 degrees LESS than the actual temperature you will be sleeping in. But everyone is different, some sleep colder than others - you’ll learn over time if the rating on the bag meets your comfort levels
If you don’t have a cold weather/winter sleeping bag, there are other options:
Double up 2 bags together! Put one inside the other
Add a down camping blanket or quilt
Add a liner, there are ones that go inside as well as outside. The option that goes IN the primary bag are preferable. They are generally pretty lightweight and comfortable inside the bag. One option to consider is the Thermolite Reactor by Sea to Summit.
Bring an extra blanket to put under your sleeping bag. You can also wrap it around the top but be careful as that will sometime trap in the condensation from your body and prevent it from escaping from the bag
A good sleeping pad is critical to have a layer between your bag and the bottom of the tent. You need a layer of air between the bag and the ground
Consider putting 2 pads on top of each other in winter to further improve the insulation value
Use a closed-cell foam pad next to the ground and a self-inflating pad on top to get the best insulation from the cold ground. The foam pad also serves as insurance in case the self-inflating pad gets punctured. Use reflective side up
Most important thing ... a good beanie hat! Nearly all your heat will be lost through your head, so its critical that you need you head covered
When its really cold, if you’re a skier or snowboarder than bring your balaclava - these are better because they won’t slip off in the middle of the night.
Fresh pair of sock before going to bed
Get out of any sweaty clothes if you’ve had them on all day - this includes a base layer
Next day change of clothes go in the bottom of your sleeping bag - you’ll be happy in the morning, plus this prevents your feet from hitting the outside of the tent and transferring condensation to your body
Put your gear and backpacks between you and the side of the tent - avoid allowing your sleeping bag to touch the sides of the tent
Hot water in a Nalgene bottle - at your core of the body - not at the feet
Always have a bottle of water inside the tent near the entrance so you have it if you need it or when you first get up in the morning. Upside down if you can, inside a boot works well - just make sure the lid is closely tightly. Upside down is so the lid won’t freeze closed.
Go to the bathroom BEFORE going to bed - a full bladder will mean you’re in for a cold night and getting out of the tent in the middle of the night is even worse