Instructions for Setting a Barometer
This barometer was designed to give the user accurate air pressure readings from sea level to an altitude of 6000 feet. Before leaving the factory, your barometer was calibrated to the standard air pressure at sea level. For your barometer to give you optimum results, you will have to recalibrate it to your local barometric pressure before use.
Locate your barometer in an area where it will be undisturbed. Do not position it in direct sunlight, as this may cause inaccurate readings.
You will need to calibrate your barometer to your location. This can be done by getting the local pressure from a local radio or television station. Use a small slotted screwdriver to turn the small screw on the back of the barometer case to adjust your barometer until the black pressure indicator hands points to a reading that corresponds to your known local barometric pressure. Your barometer has now been calibrated. Never turn the screw more than one complete rotation.
For daily operation of your barometer, place the gold pointer attached to the lens directly over the black pressure indicator hand.
This will allow you to measure any change in pressure that may have taken place. It is the amount of change in pressure and the rate of change that will be an indicator of the weather.
The following basic rules will hold true in using the barometer to predict weather conditions:
- A fast rise in barometric pressure means good weather of short duration
- A rapid drop in barometric pressure means disturbances nearby - showers of short duration
- Regular elevation of barometric pressure will usually indicate clear, dry weather conditions (cold and dry in the winter)
- A drop of 2-3 tenths of an inch per 24 hours indicates a depression some distance away
- Drops of 1-2 tenths per hour means disturbances nearby, of short duration
- Steep drops of 6-10 tenths within a 4-5 hour periods indicates coming rain and a storm with strong winds
Operating tolerance: +/- 0.5”