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name: trading-session-timezones description: Trading session timing for MES/MGC futures with timezone handling. Use when implementing session-based entry/exit logic, ORB time windows, RTH detection, or handling global market overlaps.

Trading Session Timezones - MES/MGC Futures

Context: Session timing for micro futures (MES/MGC) trading Critical For: Opening Range Breakout (ORB), session-based entry/exit timing Platform: NinjaTrader 8 with Rithmic data feed Universal Path: ${PROJECT_ROOT} Executors: ${BRAIN} (Reasoning), ${HANDS} (Gemini Flash via delegation_bridge)

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Session Times (Eastern Time)

RTH (Regular Trading Hours) - Primary Trading Window

CopyOpen:  09:30 ET
Close: 16:00 ET

Best for: ORB (9:30-10:00 setup), MOMO, all high-volume strategies Volume: Highest - 50-200 ticks/min during active periods Spread: Tightest (1-2 ticks typical)

Globex (Extended Hours)

CopyOpen:  18:00 ET (previous day)
Close: 17:00 ET (current day)

Best for: Trend continuation, overnight gap setups Volume: Moderate - 5-50 ticks/min Spread: Wider (2-4 ticks typical)

Pre-Market

CopyOpen:  04:00 ET
Close: 09:30 ET

Best for: ORB preparation, pre-market analysis Volume: Low - 5-20 ticks/min Spread: Wide (3-5 ticks)

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Code Implementation

Detecting Session State

Copyprivate bool IsRTH()
{
    TimeSpan now = Time[0].TimeOfDay;
    TimeSpan rthOpen = new TimeSpan(9, 30, 0);
    TimeSpan rthClose = new TimeSpan(16, 0, 0);

    return now >= rthOpen && now < rthClose;
}

private bool IsORWindow()
{
    TimeSpan now = Time[0].TimeOfDay;
    TimeSpan orStart = new TimeSpan(9, 30, 0);
    TimeSpan orEnd = new TimeSpan(10, 0, 0);

    return now >= orStart && now < orEnd;
}

Timezone Conversion for Multi-Market Trading

Copy// Convert ET to other timezones for global session awareness
private DateTime ConvertETToLocal(DateTime etTime)
{
    TimeZoneInfo et = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
    TimeZoneInfo local = TimeZoneInfo.Local;

    return TimeZoneInfo.ConvertTime(etTime, et, local);
}

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Optimal Trading Windows (Priority Tiers)

Tier 1: Best Execution Quality (Target 100% of trades here)

Copy09:30 - 12:00 ET  Morning session (ORB, MOMO, high volatility)
13:00 - 15:00 ET  Afternoon trends (RMA, TREND strategies)

Characteristics:

• Tightest spreads (1-2 ticks)
• Highest volume (100+ ticks/min)
• Best fills (slippage ≤ 2 ticks)
• Fastest execution (< 50ms)

Tier 2: Acceptable Quality (Use selectively)

Copy08:00 - 09:30 ET  Pre-market (ORB setup, low risk entries)
15:00 - 16:00 ET  Close (end-of-day moves)

Characteristics:

• Moderate spreads (2-3 ticks)
• Moderate volume (20-50 ticks/min)
• Acceptable fills (slippage ≤ 3 ticks)

Tier 3: Avoid (Only for specific strategies)

Copy19:00 - 22:00 ET  Evening Globex
04:00 - 08:00 ET  Early morning

Characteristics:

• Wide spreads (3-5 ticks)
• Low volume (< 20 ticks/min)
• Poor fills (slippage > 3 ticks)

Dead Zones (Never Trade)

Copy16:00 - 18:00 ET  Session transition (Rithmic may disconnect)
22:00 - 04:00 ET  Overnight (ultra-low volume)

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ORB Strategy Timing Requirements

Setup Phase (9:30-10:00 ET)

Copyprotected override void OnBarUpdate()
{
    if (!IsORWindow() || !IsFirstTickOfBar)
        return;

    // Capture high/low during OR window
    if (High[0] > sessionHigh)
        sessionHigh = High[0];
    if (Low[0] < sessionLow)
        sessionLow = Low[0];
}

Trade Phase (10:00-12:00 ET)

Copyprivate bool IsORTradeWindow()
{
    TimeSpan now = Time[0].TimeOfDay;
    TimeSpan tradeStart = new TimeSpan(10, 0, 0);
    TimeSpan tradeEnd = new TimeSpan(12, 0, 0);

    return now >= tradeStart && now < tradeEnd;
}

protected override void OnBarUpdate()
{
    if (!IsORTradeWindow() || !orComplete)
        return;

    // Execute breakout trades
    if (Close[0] > sessionHigh + TickSize)
        ExecuteLong();
    else if (Close[0] < sessionLow - TickSize)
        ExecuteShort();
}

Forced Exit (12:00 ET)

Copyprotected override void OnBarUpdate()
{
    TimeSpan exitTime = new TimeSpan(12, 0, 0);

    if (Time[0].TimeOfDay >= exitTime && Position.MarketPosition != MarketPosition.Flat)
    {
        FlattenAll("ORB time exit");
    }
}

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Global Session Overlaps (For Multi-Market Awareness)

Key Times in Eastern (ET)

Copy20:00 ET (prev day)  China market open (Shanghai 9:00 AM)
01:00 ET             Tokyo market open (Tokyo 3:00 PM)
03:00 ET             London pre-market
08:00 ET             London RTH open
09:30 ET             New York RTH open ← PRIMARY FOCUS

Overlap Impact on MES/MGC

• London + NY (8:00-16:00 ET): Highest volume period
• Asia hours (20:00-03:00 ET): Lower volume, wider spreads
• NY solo (15:00-16:00 ET): Moderate volume, end-of-day positioning

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Calendar-Based Filters

High-Impact News Days (Avoid or Trade Cautiously)

Copy// Example: FOMC days - avoid 2 hours before/after announcement
private bool IsFOMCDay()
{
    // Hardcode FOMC dates or check economic calendar API
    DateTime[] fomcDates = { new DateTime(2025, 1, 29), new DateTime(2025, 3, 19) };
    return fomcDates.Contains(Time[0].Date);
}

protected override void OnBarUpdate()
{
    if (IsFOMCDay() && Time[0].TimeOfDay >= new TimeSpan(12, 0, 0))
    {
        // Pause trading or reduce position size
        return;
    }
}

Weekly Patterns

Copyprivate bool IsFriday()
{
    return Time[0].DayOfWeek == DayOfWeek.Friday;
}

protected override void OnBarUpdate()
{
    // Reduce position size on Friday afternoons
    if (IsFriday() && Time[0].TimeOfDay >= new TimeSpan(14, 0, 0))
    {
        positionSizeMultiplier = 0.5;  // Half size
    }
}

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Rithmic Data Feed Session Behavior

Expected Tick Frequency by Session

Copyprivate void MonitorTickHealth()
{
    int ticksPerMinute = tickCount / minutesSinceOpen;

    if (IsRTH() && ticksPerMinute < 20)
        Print("WARNING: RTH tick frequency low - Rithmic may be degraded");
    else if (!IsRTH() && ticksPerMinute < 5)
        Print("INFO: Normal overnight low volume");
}

Session Transition Handling

Copyprotected override void OnBarUpdate()
{
    // Close positions before session transitions to avoid gaps
    TimeSpan sessionTransition = new TimeSpan(15, 55, 0);

    if (Time[0].TimeOfDay >= sessionTransition && Position.MarketPosition != MarketPosition.Flat)
    {
        FlattenAll("Pre-session close");
    }
}

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Performance Optimization

Cache Session Checks (Don't Recalculate Every Tick)

Copyprivate bool cachedIsRTH = false;
private DateTime lastSessionCheck = DateTime.MinValue;

private bool IsRTHCached()
{
    if (Time[0] != lastSessionCheck)
    {
        cachedIsRTH = IsRTH();
        lastSessionCheck = Time[0];
    }
    return cachedIsRTH;
}

Execution Speed Target

• Session state checks: < 0.1ms
• OR window detection: < 0.1ms
• Forced exit logic: < 1ms total

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Quick Reference Table

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Testing Checklist

Before deploying session-based logic:

• Verify timezone conversion (ET vs. local)
• Test OR window detection (9:30-10:00 exact)
• Test forced exit (12:00 ET exact)
• Verify session transition handling
• Test on historical data with session gaps
• Verify tick frequency monitoring works
• Test calendar filters (Friday, FOMC, etc.)

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Related Skills

• wsgta-trading-system - Strategy-specific session rules
• universal-or-strategy - Project context
• apex-rithmic-trading - Data feed session behavior
• wearable-project - Portability standards