Camping and the Dew Point
We've all gone to bed on a nice clear evening and woken up to our tent, vehicles and bedding wet. But why does that happen if there is no rain? It's because of the morning dew.
What is Dew?
Before we look at what dew is, lets go back to science class. Materials exist in three forms - solid, liquid and gas. The form that material exist in depends on the amount of heat that is applied to it.
Lets look at water (H20) for example.
When temperatures drop down to 0C (32F) water begins to freeze. Ice is the SOLID form of H20. When the temperature warms up, the water changes from ice to what we think of as "water". "Water" is the LIQUID form of H20. What happens if you heat up water? When you apply heat (over 100C) the water changes from liquid to a vapor (think of boiling water). Vapor is the GAS form of H20.
Dew occurs when moisture (or water) is the air changes from a gas to a liquid (called condensation). When camping in a region with high humidity, and cool overnight temperatures, the water in the air will shift from vapor to liquid, coating everything in a damp morning dew.
Tips for Camping with Dew
Although we can't control the weather (too bad really), there are things we can do to help reduce the effects of a morning dew. Dew (and condensation) can effect things both inside and outside our tents.
#1. Pack it Up. Pack chairs and other fabric items in the vehicle for the night. Keeping items that can be damaged by moisture inside a solid structure (like a vehicle or building) is the best protection against morning dew. Keeping these items away from the dew will prevent mold from growing on fabrics, and rust from forming on metal.
#2. Throw a Tarp on it. For items that can't be packed in a vehicle easily, throw a waterproof tarp like the FE Active Galaopagos Rainfly to keep them covered and not exposed to the moisture. Tarps are waterproof coverings are great for more than just throwing over or under a tent.
#3. Waterproof Tents. Not all tents are created equal. To help keep you (and your gear) dry inside your tent, be sure to purchase a tent that has a high waterproof value. You'll often notice that large, cheaper tents don't offer much rain protection. Purchasing a tent with a full rain fly like the FE Active Escondido or Grindavik will keep the moisture away from the top and sides of the tent, greatly protecting you from the moisture.
#4. Ample Ventilation. Even our breath can work against us from time to time. As we breathe, we release water vapor out into the air via our lungs. Like outside the tent, these particles can change into liquid and coat the inside of the tent. Be sure to leave your vents cracked open to allow air circulation. This will not only provide you with fresh air to breathe, but it will help keep the vapor and heat from becoming trapped inside the tent.
#5. Use your Stakes. You know those ground stakes and ropes that come with your tent? Use them! Keeping our sleeping gear away from the walls of the tent is very important when keeping out moisture. Be sure to use all the stakes and ropes (called guy wires) included with your tent when you set it up. These are designed to help keep the fabric stretched out (away from the people inside), and to aid in stability during windy conditions.
#6. Cook outside. We've all been temped to cook inside our tents, especially in bad weather. There are several reasons not to (did someone say fire hazard?), but one reason is to not allowing the water vapor from the boiling water to fill your tent. The water will condense, and soak your gear inside.
#7. Leave the Wet Clothes Behind. Come to bed with dry clothes only. Don't feel tempted to take off and "dry" clothes inside the tent. Once again, these water vapours will become trapped inside and settle on your dry sleeping bag and pillow.
There are times where there's nothing we can do. We've followed the steps above and still moisture is inside the tent. That's life unfortunately, and one of the challenges with sleeping outside. When worst comes to worse, carry a quick drying microfiber cloth to wipe down the fabric to remove the water from inside the tent.
Remember though, once you do this, don't leave it inside the tent! It will defeat the purpose!