Reference Regular Trading Hours (RTH) Session

For a contract's CME Globex trading hours on a given calendar day beginning after that contract's RTH session on that calendar day and ending no later than 4:00 p.m., Chicago time, on that same calendar day, the Reference Regular Trading Hours (RTH) Session is that contract's second-previous RTH session. For a contract's CME Globex trading hours beginning at or after 4:00 p.m., Chicago time, and ending no later than the start of that contract's next RTH session, the Reference Regular Trading Hours (RTH) Session is that contract's previous RTH session. Chicago Mercantile Exchange Glossary