Possible Clues:

• In exchange one might bargain around round me for the weather
• That makes the bar begin to be subject to pressure
• For drink round what must be read under pressure
• That shows what pressure there is to barter around around me
• This may tell you it's fine to ram beer with
• It goes down when the rain comes down
• Instrument to measure atmospheric pressure
• Barter around round me for the weather
• Indicator of change, sign mostly displayed in centre of trade
• Term a bore devised for a measurer of pressure