‘Standard’ (is the word I think we should use) Barometric pressure at sea level is 29.92 inches mercury but can and does have a normal range 29.5 to 30.2 ish.
Extremes can happen beyond that. 26” in a typhoon is possible and I think they’ve registered 32” in Siberia during a high pressure event. I learned all this no one needs to know crap in a former life as a pilot. Lol