The main cause of daytime overheating in your tent is simple: the sun…
…or, in technical parlance, solar gain—the increase in thermal energy in any space or structure as a result of it absorbing solar radiation, i.e. sunlight.
In short, tent fabric allows most solar wavelengths to pass through and heat up the inside of your tent. This creates a kind of Greenhouse effect, with heat coming in but having limited means of getting back out.
How to Prevent Daytime Overheating
To avoid your tent turning into a sweltering torture chamber during the daytime, take the following steps:
- Make use of natural shade from trees and bushes
- Open all ventilation zips
- Maximize airflow when pitching your tent by ensuring there is a gap between the tent body and fly
- Leave the rainfly off if there’s no risk of rain
- Buy a lighter-colored tent—dark colors absorb more energy from UV radiation
- Wait until sundown to pitch your tent
- Suspend a tarp above your tent to provide shade instead of using a rainfly
The main source of nighttime overheating is not anything outside your tent but, rather, what’s inside it: humans.
We humans naturally heat our bodies to an average temperature of 98.6° Fahrenheit, which is normally much warmer than the temperature of the ambient air that surrounds us. While outside temps cool down as the day progresses, our body heat and the warm air from our breathing essentially cancel out that decrease in temperature and can leave things a little bit stuffy inside our tent without adequate ventilation.
How to Avoid Nighttime Overheating
The first step to ensuring your tent isn’t intolerably toasty in the evening is to make sure it is well ventilated in the evening. On particularly hot days, the sun can heat up the inside and contents of your tent and the stored heat or “thermal mass” will release slowly after sundown.
Other tips that can help reduce nighttime overheating include:
- Ditch the rainfly if the skies are clear and forecasts are good
- Opt for a larger tent—smaller tents maximize thermal efficiency; big ones do the opposite
- Store your gear outside your tent so your body heat is dispersed throughout more cubic footage
Other Tips for Staying Cool in Your Tent
1. Pitch your tent near a river or lake to take advantage of the cooler air.
2. Take a dip before bedtime to lower your core temperature.
3. Reflect heat away from your tent by laying reflective thermal survival blankets on the tent wall most exposed to the sun.
4. Bring along a camping cooler if car camping or not venturing too far from the roadside.
5. If backcountry camping, hike into higher ground—where temps will be lower—before pitching your tent.