How to Sleep Warmer in a Tent Without Buying a Whole New Setup
Cold tent sleep usually comes from three things: heat escaping into the ground, moisture building inside your sleep system, or wind moving across an exposed campsite. You can improve all three before spending money on a new sleeping bag.
Start underneath you
A sleeping bag keeps warm air around your body, but compressed insulation under your back does very little. The sleeping pad matters because it slows heat loss into the ground. If the night will be chilly, stack a foam pad under an inflatable pad or add a folded blanket under your torso.
Change clothes before bed
Damp socks and base layers steal warmth slowly. Put on dry sleep layers, a clean beanie, and loose socks before getting into the bag. Avoid overdressing to the point that you sweat, because moisture will make the early morning feel colder.
Pick a protected site
Pitch away from low spots where cold air settles. Use natural windbreaks when campground rules allow, and stake the rainfly properly so the tent can ventilate while still blocking wind-driven moisture.
Safety note: never run a fuel stove or heater inside a tent unless the product is explicitly designed and rated for that use.