Calendars not in sync between iMac and iPad

My iCloud calendars are not in sync between my iPad and my iMac. For example, I have an appointment on Wed., Sept. 2, at 10:30 a.m. That is the appointment's correct time here in my Baltimore, MD, time zone, and indeed it's the time shown on my iPad, which is where I actually entered the appointment. But it shows as 7:30 a.m. in the iCloud calendar in my web browser on my iMac. Possibly the iCloud calendar in my web browser thinks my correct time zone is Pacific time — I don't know that for sure, though. My question is: how can I get the iCloud calendar in my iMac web browser to agree with my iPad about what time zone I'm in, i.e., the Eastern time zone? In other words, I want the times shown in the iCloud calendar in my web browser to be the same as the (correct) times shown on my iPad. Thanks in advance for any help you can give me.