In the mountains there is a temperature decrease with elevation gain.  Here is why that happens and a way to calculate approximately what the decrease will be.

Anyone that has spent some time in the Rocky Mountains will have noticed that it is always much colder at the tops of the mountains than at the bottom.  Part of the reason for this is that the top tends to be windier and has a wind chill, making it feel colder than it is.  But, it does actually become colder in temperature as you climb higher in the mountains.

Why Does Temperature Decrease With Elevation Gain?

This is  bit complicated, but I’ll do my best to simplify it here.  The reason for this is similar to the saying that the air is thinner at higher elevations.  At lower elevations there is more pressure, which means that within a certain area there are a lot of air molecules.  As you go up in elevation the pressure decreases because those same number of air molecules expand and cover a larger area, which is king of like the air being thinner.

At the higher elevation there is less pressure because the air molecules have spread out.  As the air expands it cools and thus the temperature is lower.

Mount Timpanogos in Utah is always much colder at top then in the valley below. Photo via Flickr.

Is There A Calculation To Determine The Temperature Decrease With Elevation Gain?

Yes.  There is a general rule that you can use to help calculate the temperature change as you go up or down in elevation.  In general, the temperature decreases 3.5 degrees F for every 1,000 feet of elevation gain.  Likewise, the temperature increases 3.5 degrees for every 1,000 feet of elevation descent.

Note – this is not exact and is just a general rule to help you get an idea of what the temperature difference may be.  Other factors influencing the temperature are sun, clouds, or wind.

Hyalite Peak in Montana is much cooler than down in Bozeman. Photo via Flickr.

Why Is It Important To Know That The Temperature Decreases As You Go Up In Elevation?

It is crucial to at least have a basic understanding of this fact for anyone that spends time in the outdoors or in the mountains.  This is important because it can have a serious effect on your hike in the Rocky Mountains.  You need to make sure you bring the right gear and are warm enough.

For example, it may be 75 degrees F where you live at 5,000 feet.  But, if you plan to hike towards a mountain that is 10,000 feet high, the temperature there will be much colder.  Doing the calculation – (5,000 feet higher * 3.5 = 17.5).  So, the top may be about 18 degrees colder or 57 degrees.  Then on top of that it may be windy, which will make if feel even colder.

You need to know this so that you can always be properly prepared and bring along the right hiking gear if you are hiking with kids.