The trading day ends at 16:00, and the next one starts at 17:00
Futures don't follow the calendar. The session that opens Sunday at 17:00 CT runs almost continuously until Friday at 16:00 CT, broken only by a one-hour maintenance halt each weekday afternoon. So a fill at 16:59 CT Monday and one at 17:01 CT Mondaybelong to two different trading days, even though your wall clock says the same date.
This is the single most common reason a journal's daily P&L disagrees with a broker statement: the journal bucketed an evening trade into the calendar day it happened on, and the broker bucketed it into the next trading day. ExpectancyIQ uses the 17:00 CT rollover everywhere, so the two agree. The longer explanation is here, including what it does to your win rate by day of week.
What this page does and doesn't cover
The live status above tracks the regular weekly schedule for CME Globex equity index futures. It does not model exchange holidays or early closes — Thanksgiving, Christmas Eve, Good Friday and the rest all shift the schedule, and this page will still show the normal one. Check the CME's own holiday calendar before trading around a holiday.
Energy, metals and treasury products keep near-identical Globex hours but have their own product calendars, so treat the times above as the equity index schedule specifically.
Sizing the trades you take in those hours
Once you know the session, the next questions are what a contract is worth and how many to trade — the contract size calculator and the position size calculator handle those.