Here's a quote directly from the pages of In Persuit of Giant Bass by Bill Murphy. "While most anglers credit pre-frontal conditions for prompting good fishing and bright, cloudless, post-frontal weather for causing bass to shut off, my studies point to barometric pressure,as having a more important influence on big bass activity. Air temperature, cloud cover and wind direction are only symptoms of a larger weather system, and the barometric pressure associated with the weather system is the key to active and inactive periods."