I don’t have a lot of confidence in the accuracy of small portable barometers. You must remember that they need to be in a stable position for a period of time to set. So, after any boat run, the air pressure change created in your boat from the air blowing through will affect the reading. Just something to keep in mind.
Probably the best fishing is on a falling barometer when a storm is moving in. The fish almost always turn on for a period of time. Next would be a stable barometer, where the pressure has been stable either high or low for at least 3 days, the fishing is usually pretty good. When the pressure is very high, normally indicated by blue bird skies, light winds and particularly, if the pressure has just gone high – the fishing is normally going to be off. Probably the worst fishing of all is on a very fast rising barometer as is the case where a thunder storm has moved through and then the wind changes quickly and turns hard out of a new direction.
One last note on barometric pressure. I don’t personally feel river fish are as affected by barometric changes as lake fish are. So, in unfavorable barometric conditions hit the river!
-J.