Google Calendar Help
Calendar Embedded in a Google Site Displays Wrong Time Zone
You have to set your time zone in your user settings. When in the site apps, there's a link next on the top of the page.
https://sites.google.com/site/sites/system/app/pages/meta/dashboard/userSettings. if your BMail account has been migrated to the new account
infrastructure, click on the Options Icon in the upper left hand section of the page and drag your mouse to the User Settings link and click. Change Time Zone to GMT-05:00 Eastern TIme - New York and click save changes.
It will default to Pacific time if you don't set anything.