How to Account for Weather Conditions When Using an Altimeter

How to Account for Weather Conditions When Using an Altimeter
You probably purchased your altimeter so that it could tell you exactly how high you are at any given moment, a useful feature when hiking, climbing and navigating. In reality, however, using an altimeter is a process of your telling the altimeter the altitude as much as it is your reading the altitude on the altimeter. This is because the altimeter is a simple device that relies on a barometer to gauge changes in altitude. Because the reading is completely linked to changes in air pressure, changes in air pressure not related to altitude change will affect the altimeter's reading and limit its accuracy.


Difficulty: Moderate

Step 1
Set the altimeter before you use it. You need to set the altimeter when you first get it and again before each new hike or adventure. This allows the altimeter to adjust for the current weather and ensures you will begin with the correct altitude. Simply set the altitude when you are at a location where you can accurately designate an altitude on a topographic map or a sign.
Step 2
Test the altimeter's accuracy. It can be very difficult to detect changing weather that will affect your altimeter's accuracy. To keep it accurate, check the altimeter against designated altitudes using a map or physical marking. You'll want to use recognizable landmarks, such as trail crossings, peaks, bridges and parks. Read your altimeter when you come to such landmarks, and if it is off, recalibrate it by setting it to the designated altitude.
Step 3
Check your altimeter in the morning or after stopping. Take a reading of the altimeter when you first stop. Write it down if you need to, and then double-check it before you start hiking again. If it reads differently, it is obviously not because of a change in altitude. Recalibrate it based on a map reading or physical marking as soon as you can.
Step 4
Use the altimeter as a weather indicator. If the altitude reading is rising and you're not gaining altitude, it indicates dropping air pressure. This is a sign of an oncoming storm. If the altitude reading is dropping without actively descending, it indicates rising air pressure, which relates to better weather on the horizon.
Step 5
Don't forget temperature. More expensive altimeters should be able to compensate for the effects of temperature, but inexpensive models can be impacted by changes in temperature. Try to keep the altimeter at the temperature where it's being used, as opposed to deep in your pocket when it's freezing outside. Hang it on your jacket, for instance. Again, recalibrate to maintain accuracy.

Article Written By Joe Fletcher

Joe Fletcher has been a writer since 2002, starting his career in politics and legislation. He has written travel and outdoor recreation articles for a variety of print and online publications, including "Rocky Mountain Magazine" and "Bomb Snow." He received a Bachelor of Arts in political science from Rutgers College.

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