How do you set a barometer ?

Question

I have some numbers around the dial from 25.5 to 31 . There is a small hole in the back but not sure what to do, any advice would be great.

Answer 1

The girl doing the weather forecast tells us what the pressure is during a stable period OR you can phone your local weather station - Cardington for Bedford for my local example.

RoyS

Answer 2

I just done what rx8mate said and it worked so they are right

Answer 3

I used this site recently works good now.

http://www.metlink.org/data/review.php?I...

Answer 4

The reason you have an adjusting s***w in you barometer is that you need to compensate for your altitude over the sea in order to read the correct information. Imagine you were living on the top of a mountain and didn't adjusted anything; you would constantly read that you were in a low pressure with rain, wind, etc. even if the sun shines.

Simply find the pressure from any place close to you, turn the adjusting s***w to match that value and ... enjoy!

From what you write, I guess you are American and you barometer is therefore graduated in inches of Mercury. The average pressure is 29.9 inches. In Europe, we use hectoPascal (formely known as millibars) and 29.9 in Mg correspond to 1013 hPa.

Answer 5

It sounds like you have an aneroid (dial-type) barometer.  Inside the little hole is probably a thing you can turn with a flathead screwdriver.  This will allow you to set the barometer to the sea-level pressure.

How to get sea-level pressure?  Well the best way (but not so likely) is to have another barometer that's already been set right next to you.  But the most realistic way is to find a weather station near you online, see what the pressure is in inches, and then with the screwdriver, set your barometer to that.  If the weather station you got it from is within 10 or 20 miles of you, and the weather is pretty placid outside, you can be sure you have a good fix.