I watch when it drops below 29.5 Hg on down (29.0 Hg or mb; millibars) or when it swings up past 30.0 mb. That's my reference for "highs" or "lows" on my Barometer. Remember to adjust yours to your local Wx reading, they have a slot shaft in the back of the meter for that. I love my old dial Aneroid barometer. They last forever, too. Mines kicking about 35 years...
(That's not mine, pic is for low and high reference...)
Hey Rebel, what do you consider low and high pressure? Perhaps a stupid question, but I just got a weather station so now I can start tracking barometric pressure. Right now the numbers don't mean much to me, been around 28-29% in the south metro the past few day and I don't know if that's low, high or middle.
Low pressure signals a front moving in, (Bad weather, wind may be from the east or north) which usually puts them "on the feed", can have some hot and fast action. Likewise, a swing in the other direction, a high pressure system , (wind from the west or south) which signals clear skies and sunny weather, may do the same. The key to me, anyway, seems to be hitting it just as either front moves in. An extended low or long high may result in poor fishing. Remember the old adage, which also has to so with the pressure:
"Wind from the east; fish bite the least...wind from the north , the fisherman goes not forth, wind from the south, blows the bait in the fish's mouth; wind from the west, is when the fishing is best".