Overnight high / low

The overnight high and low are the highest and lowest prices traded between the futures session open and the start of regular trading hours, projected onto the rest of the session. On CME index futures that window runs from 17:00 Chicago time to the 08:30 CT cash open, so the levels describe the range built before the regular-hours auction begins.

Senzoukria · Glossary · Updated September 2026

Which bars count

Futures trade almost around the clock, but the bulk of the volume on index contracts tends to arrive during the regular hours that mirror the cash equity session. The overnight, sometimes called ETH for extended trading hours, is everything from the session open at 17:00 CT until the RTH open. Its high and low are the extremes of the bars in that window and nothing else; the regular hours that follow do not modify them.

  • The RTH open for CME equity index futures is 08:30 Chicago time, which is 930 minutes after the 17:00 CT session open. Because both times are in the same time zone, the offset stays correct across daylight-saving changes, which happen on Sunday when the market is closed.
  • Other contracts have a different RTH open. The offset is a setting, not a constant.
  • The levels only make sense when the session has bars on both sides of the boundary. An overnight range with no regular hours loaded yet has nothing to project onto.

How the open uses them

  • An RTH open inside the overnight range means the regular-hours auction starts in balance; the overnight extremes are the first places to look for a test.
  • An open outside the range leaves the whole overnight on one side. Whether price accepts the new area or returns into the range is visible in the first footprints.
  • The overnight is thinner than regular hours, so its extremes can be set by a small amount of volume. A level built on a few contracts is easier to run through than one built on a heavy auction.

In Senzoukria

The overlay is Overnight High/Low in the Profiles & levels group of the indicator panel. Its parameter RTH open (min after 17:00 CT) defaults to 930, which places the boundary at 08:30 Chicago time for the CME index contracts, and it can be changed for instruments with a different regular session. The levels are drawn only when the loaded session contains bars on both sides of the boundary. The desktop's history screens also state that CME futures trade from Sunday 17:00 to Friday 16:00 Chicago time with a daily break from 16:00 to 17:00, which is the session frame these levels rely on.

Common mistakes

  • Confusing the overnight range with the prior session range. The overnight belongs to the current session; the prior session ended at the last daily break.
  • Using a globe-time or UTC boundary for the RTH open, which drifts by an hour twice a year against Chicago time.
  • Reading an overnight extreme as a strong level without looking at how much volume set it.

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Frequently asked questions

Does the overnight range include Sunday evening?
For Monday's session, yes. The week opens on Sunday at 17:00 Chicago time and that evening belongs to the Monday trade date. The overnight high and low for Monday are therefore measured from Sunday 17:00 CT until Monday 08:30 CT.
Why are the levels missing on my chart?
Most often because the session has not yet reached the RTH open, or because only regular-hours bars are loaded. The overlay needs bars before and after the boundary. Check that extended-hours data is being loaded and that the RTH offset matches your contract.
Should I trade the overnight extremes directly?
They are reference prices, not entries. Their value comes from what happens when price returns to them, which the footprint and the DOM show at that moment. The site's MNQ guide covers session choices and why settings transferred from another contract need re-checking.

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