6 Essential Weather Report Details Every Camper and Backpacker Should Know Before Heading Into the Elements

You probably already know how to read temperature and precipitation forecasts. Those are the ones you check every morning to decide which jacket to grab as you're heading out the door.

But when you're heading out into the backcountry to brave the elements, it's important to pay more attention to the details of a weather report. When you're considering what to add to your backpacking checklist, you need to know a bit more than just temperature and rain forecasts.

1. Relative Humidity

Relative humidity is a ratio of how much water is currently dissolved in the air, relative to how much water the air could potentially hold at its current temperature. When the relative humidity is around 80 percent, the air starts to feel "moist" and "sticky." When relative humidity is low, people say that the air feels "dry."

Relative humidity has a big impact how your body controls its moisture. You'll have problems drying out your gear or clothing in environments that have high humidity, and you may feel like you're constantly covered in sweat. Your hair may start to curl at humidity above 90 percent. Conversely, low humidities will make you more dehydrated, even thought you might feel less sweaty.

2. Dew Point

The temperature at which water will condense out of the air, for the given humidity, is called the dew point. If the temperature drops below this point, you can expect condensation to start forming everywhere.

Condensation happens first around colder surfaces like the ground or metal objects. You might also find condensation happening at temps above the dew point if you're in an especially humid area, like a poorly ventilated tent.

If you want to avoid waking up to a wet sleeping bag, make sure your shelter is well-ventilated to avoid excessive humidity building up. It also helps to be in an area that might hold heat better -- like under thick, low foliage -- so that the air stays warmer and doesn't drop below the dew point.

3. Atmospheric Pressure (aka "Barometric Pressure")

There are many different ways that atmospheric pressure is reported, but knowing the exact number and unit isn't too important. Instead, you should focus on the trend -- is the pressure generally going up or down?

If the air pressure is going up, you can expect the skies to clear up. Since the air is getting heavier and sinking down, it's warming which prevents clouds from forming.

If the air pressure is going down, you can expect clouds to start forming. Since the air is generally rising, it will start to cool and any moisture it's holding will condense into clouds, since it's crossing below the dew point. More information about air pressure here.

4. Cloud Cover

When skies are clear, temperatures fluctuate a lot between the day and night. Sunlight will heat the earth's surface more effectively when there aren't clouds. But at night, all of that warm air will rise up into the sky and dissipate, making it much colder on the ground.

When skies are overcast, it tends to be cooler during the day without direct sunlight. But the clouds also functions as a thick blanket that holds the warm air down towards the earth, so it won't get as cold at night.

While it might be nice to lay out under the stars on a clear night, expect it to get much colder before the morning sun starts to rewarm things. Also, with that sharp drop in temperature overnight, you're more likely to dip below the dew point and wake up with a wet sleeping bag.

5. UV Index

Anything higher than 6 means it's definitely time to put on sunscreen or protective clothing with a high UPF rating. You also probably want to be wearing sunglasses and a wide-brimmed hat to keep the sun off of your face and neck.

Make sure you check the UV Index anytime you're hiking anywhere else that doesn't have adequate tree cover or shade. It's easy to underestimate how badly you can get burned when you're hiking with no shade for hours a day.

6. Visibility

In cities, visibility can be affected by smog and other air pollution. In the backcountry, visibility is more likely to be affected by fog, mist or haze.

Generally, a "clear" reading tops out at something around 10 miles. The number can be a bit misleading, since you can often see much farther from high vantage points on clear days. With a light haze, you might see a visibility rating around 2-3 miles, and with mist or fog, it'll usually be less than one mile.

It's important to know the visibility reading if you're planning on doing a trip that relies on big views or sight seeing.

If you'd like to learn more about the conditions for an upcoming backcountry trip, check out this simple tool that shows you detailed weather history for an area.