Feeling The Pressure: Barometer Guide

April 22, 2016

Feeling The Pressure: Barometer Guide

Feeling the Pressure: Barometer Guide

Your new aneroid barometer is a precision instrument that measures changes in atmospheric pressure and the movement is temperature compensated to achieve greater accuracy. Because changes in pressure influence weather conditions, barometers are traditionally used to make weather forecasts.

A barometer can be located anywhere in your home but we recommend that it is kept away from direct sunlight and sources of heat.

When your Barometer first arrives

Before leaving the factory your new barometer will have been set to give the correct sea-level reading. However as atmospheric pressure drops as altitude increases it will be necessary to make an adjustment for your area before mounting your barometer.

1. Find the current pressure for your location by going to www.bbc.co.uk/weather and entering your postcode. TV weather forecasts often give the air pressure during nightly broadcasts, an ideal time to set your barometer.
2. Using the included set screw carefully adjust the movement hand to the current barometric pressure reading you have just collected.
3. WARNING: Do not overturn the barometer movement as this could tighten the mechanism and damage the instrument.
4. Mount your barometer in its desired location and leave to acclimatise for a few days.

Reading your Barometer

The rise and fall of atmospheric pressure indicates approaching weather conditions. By following the procedure below you should be able to make a daily weather forecast from your own home.

1. Tap the instrument lightly to release any latent build up in pressure.
2. Adjust the settable pointer, controlled by the knob in the centre of the glass casing so that it sits directly over the black pressure indicator.
3. At the next reading you will notice in which direction and to what degree the pressure has changed.

Making a Weather Forecast

> A clockwise movement indicates rising pressure, which usually means a change for the better or continued good weather. 

> An anti-clockwise movement indicates falling pressure and deteriorating conditions.

> A steady barometer denotes continuation of prevailing conditions.

Trend, rate and magnitude of pressure change should also influence your overall interpretation. In the event of a rapid fall you can expect a more dynamic alteration in weather conditions over the next 24 hours. Remember a barometer measures current air pressure. As such the words Fair, Change, Rain etc. should not be used for a forecast. It is more important when reading your barometer to look at which way the pressure is moving as this indicated approaching weather conditions.

Maintaining your Barometer

The benefit of an aneroid barometer is it will not require any type of regular servicing or calibration. Once set you should not need to constantly check the pressure reading via other sources or change your dial and there should also be no need to correct for altitude.

Converting Inches of Pressures to Millibars

> To convert inches to millibars simply multiply you're reading by 33.86.
> To convert millibars to inches multiply by 0.02953

To print this useful barometer guide click here. We hope the above steps have been helpful but if you would like further advice or assistance feel free to email a member of our sales team.

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