Banjo Barometer Weather Prediction

mickrourke

Hi,
I have a quick question about barometers. I have a nice banjo one hanging in the hallway which i have calibrated with met eireanns site for Kildare, and i also have a digital one which diplays the pressure also calibrated. The two together seem to be very accurate or at least there is only ever 1-2 between the two and they move in the same direction. So those being equal and the banjo being reasonably accurate (says 1019 at the moment - Celbridge, Kildare), the banjo also has written above the numbers Stormy, Change, Very Dry, etc, but I do notice that sometimes, in fact more than often, it's raining when the barometer is close to very dry, or the pressure might be 980 but not raining. So my question is how accurate are barometers at predicting the weather? and with industrialization over the last 200 years, were they more accurate, say, a 100 years ago (the barometer is 50 years old) because there would have been less cloud/precipitation due to less air pollution etc, or am i just barmy?

Thanks
(sorry that wasn't a quick question)

Paddy.1

A barometer in general is not designed to show current conditions, but conditions one may expect in the next 24/36 hrs. For example, if the pin is pointing to very dry and it is currently raining, there is a good chance that the rain will die away quickly to leave a dry period ahead. The same is true when the pin is pointing to very wet or stormy, it is an indicator of what is to come, rather than what is.

mickrourke

Thanks for that Paddy, I thought that that was the general idea alright