Estimating temperatures for trips with elevation gain.
I come across this very frequently on hiking forums where people are trying to calculate gear based upon a remote area that perhaps does not have a weather forecast. On average, temperature decreases by 5.4 degrees Fahrenheit per 1,000 feet ascended in clear weather, or 3.3 degrees if it is raining or snowing.
As mentioned above, I see a lot of people using the temperature of Yosemite Valley (4,000 feet) when planning for back-country trips at higher elevations in Yosemite which is a mistake. So lets use this simple example: Someone wants to camp on top of Clouds Rest (10,000) leaving from the Yosemite Valley on a fine day where the temperature overnight low in the valley is 50 degrees Fahrenheit. The expected temperature low on Clouds Rest would be:
50 - (6 x5.4) = 17.6
50 degrees at 4,000 (valley) with a 5.4 degree negative change per 1,000 feet (6 total) = 17.6 degrees.
A huge change!
So keep this in mind for planning any trips that include elevation change.
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